diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5baf7f205..9e2e3cbd3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -16,10 +16,10 @@ env:
   CARGO_TERM_COLOR: always
   DASEL_VERSION: https://github.com/TomWright/dasel/releases/download/v1.24.3/dasel_linux_amd64
   RUSTFLAGS: "-D warnings"
-  FUEL_CORE_VERSION: 0.19.1
+  FUEL_CORE_VERSION: 0.20.3
   RUST_VERSION: 1.70.0
   FORC_VERSION: 0.42.1
-  FORC_PATCH_BRANCH: ""
+  FORC_PATCH_BRANCH: "upgrade/fuel-core-v0.20.1"
   FORC_PATCH_REVISION: ""
 
 jobs:
diff --git a/Cargo.toml b/Cargo.toml
index 6aff3792a..966a02d8b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -45,17 +45,6 @@ chrono = "0.4.24"
 elliptic-curve = { version = "0.13.4", default-features = false }
 eth-keystore = "0.5.0"
 fuel-abi-types = "0.3.0"
-fuel-core = { version = "0.19.1", default-features = false }
-fuel-core-chain-config = { version = "0.19.1", default-features = false }
-fuel-core-client = { version = "0.19.1", default-features = false }
-fuel-core-types = { version = "0.19.1", default-features = false }
-fuel-asm = "0.34.0"
-fuel-crypto = "0.34.0"
-fuel-merkle = "0.34.0"
-fuel-storage = "0.34.0"
-fuel-tx = "0.34.0"
-fuel-types = { version = "0.34.0", default-features = false }
-fuel-vm = "0.34.0"
 fuels = { version = "0.44.0", path = "./packages/fuels" }
 fuels-accounts = { version = "0.44.0", path = "./packages/fuels-accounts", default-features = false }
 fuels-code-gen = { version = "0.44.0", path = "./packages/fuels-code-gen", default-features = false }
@@ -84,3 +73,18 @@ thiserror = { version = "1.0.40", default-features = false }
 tokio = { version = "1.27.0", default-features = false }
 trybuild = "1.0.80"
 which = { version = "4.4", default-features = false }
+
+# Dependencies from the `fuel-core` repository:
+fuel-core = { version = "0.20.3", default-features = false }
+fuel-core-chain-config = { version = "0.20.3", default-features = false }
+fuel-core-client = { version = "0.20.3", default-features = false }
+fuel-core-types = { version = "0.20.3", default-features = false }
+
+# Dependencies from the `fuel-vm` repository:
+fuel-asm = "0.35.3"
+fuel-crypto = "0.35.3"
+fuel-merkle = "0.35.3"
+fuel-storage = "0.35.3"
+fuel-tx = "0.35.3"
+fuel-types = { version = "0.35.3", default-features = false }
+fuel-vm = "0.35.3"
diff --git a/examples/contracts/src/lib.rs b/examples/contracts/src/lib.rs
index 776889b22..b6f7eab32 100644
--- a/examples/contracts/src/lib.rs
+++ b/examples/contracts/src/lib.rs
@@ -1,6 +1,7 @@
 #[cfg(test)]
 mod tests {
     use fuels::types::errors::{error, Error, Result};
+    use fuels::types::Bits256;
 
     #[tokio::test]
     async fn instantiate_client() -> Result<()> {
@@ -104,7 +105,7 @@ mod tests {
             .await?;
         // ANCHOR_END: contract_call_cost_estimation
 
-        assert_eq!(transaction_cost.gas_used, 499);
+        assert_eq!(transaction_cost.gas_used, 333);
 
         Ok(())
     }
@@ -344,10 +345,11 @@ mod tests {
         let response = contract_methods.mint_coins(1_000_000).call().await?;
         // ANCHOR: variable_outputs
         let address = wallet.address();
+        let asset_id = contract_id.asset_id(&Bits256::zeroed()).into();
 
         // withdraw some tokens to wallet
         let response = contract_methods
-            .transfer_coins_to_output(1_000_000, contract_id, address)
+            .transfer_coins_to_output(1_000_000, asset_id, address)
             .append_variable_outputs(1)
             .call()
             .await?;
@@ -406,7 +408,7 @@ mod tests {
             .await?;
         // ANCHOR_END: dependency_estimation_manual
 
-        let asset_id = AssetId::from(*caller_contract_id.hash());
+        let asset_id = caller_contract_id.asset_id(&Bits256::zeroed());
         let balance = wallet.get_asset_balance(&asset_id).await?;
         assert_eq!(balance, amount);
 
@@ -527,10 +529,10 @@ mod tests {
         let contract_methods = MyContract::new(contract_id, wallet.clone()).methods();
 
         // ANCHOR: call_params_gas
-        // Set the transaction `gas_limit` to 10_000 and `gas_forwarded` to 4300 to specify that
-        // the contract call transaction may consume up to 10_000 gas, while the actual call may
+        // Set the transaction `gas_limit` to 1_000_000 and `gas_forwarded` to 4300 to specify that
+        // the contract call transaction may consume up to 1_000_000 gas, while the actual call may
         // only use 4300 gas
-        let tx_params = TxParameters::default().set_gas_limit(10_000);
+        let tx_params = TxParameters::default().set_gas_limit(1_000_000);
         let call_params = CallParameters::default().set_gas_forwarded(4300);
 
         let response = contract_methods
@@ -628,7 +630,7 @@ mod tests {
             .await?;
         // ANCHOR_END: multi_call_cost_estimation
 
-        assert_eq!(transaction_cost.gas_used, 786);
+        assert_eq!(transaction_cost.gas_used, 546);
 
         Ok(())
     }
diff --git a/examples/cookbook/src/lib.rs b/examples/cookbook/src/lib.rs
index 79cbace5b..a388ea050 100644
--- a/examples/cookbook/src/lib.rs
+++ b/examples/cookbook/src/lib.rs
@@ -1,5 +1,6 @@
 #[cfg(test)]
 mod tests {
+    use fuels::types::Bits256;
     use fuels::{
         prelude::Result,
         types::transaction_builders::{ScriptTransactionBuilder, TransactionBuilder},
@@ -65,7 +66,7 @@ mod tests {
         // ANCHOR_END: liquidity_deposit
 
         // ANCHOR: liquidity_withdraw
-        let lp_asset_id = AssetId::from(*contract_id.hash());
+        let lp_asset_id = contract_id.asset_id(&Bits256::zeroed());
         let lp_token_balance = wallet.get_asset_balance(&lp_asset_id).await?;
 
         let call_params = CallParameters::default()
diff --git a/packages/fuels-accounts/src/lib.rs b/packages/fuels-accounts/src/lib.rs
index 956f13113..a3534de64 100644
--- a/packages/fuels-accounts/src/lib.rs
+++ b/packages/fuels-accounts/src/lib.rs
@@ -405,7 +405,7 @@ mod tests {
         let message = Message::from_bytes(*tx.id(consensus_parameters.chain_id.into()));
 
         // Check if signature is what we expect it to be
-        assert_eq!(signature, Signature::from_str("13ce336c5f239a748f20f39323e3df3237ccfe104b04f128be66f26a49abd09d3b4b19c7f07efbb708c442371feb5fc6545f2b614e1f9f336702cca3e62d0cc8")?);
+        assert_eq!(signature, Signature::from_str("df91e8ae723165f9a28b70910e3da41300da413607065618522f3084c9f051114acb1b51a836bd63c3d84a1ac904bf37b82ef03973c19026b266d04872f170a6")?);
 
         // Recover address that signed the transaction
         let recovered_address = signature.recover(&message)?;
diff --git a/packages/fuels-core/src/types.rs b/packages/fuels-core/src/types.rs
index bdf08d5c6..a29db7ad1 100644
--- a/packages/fuels-core/src/types.rs
+++ b/packages/fuels-core/src/types.rs
@@ -23,7 +23,7 @@ pub type ByteArray = [u8; 8];
 pub type Selector = ByteArray;
 pub type EnumSelector = (u8, Token, EnumVariants);
 
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
+#[derive(Debug, Clone, PartialEq, Eq, Default, serde::Serialize, serde::Deserialize)]
 pub struct StringToken {
     data: String,
     expected_len: Option<usize>,
@@ -70,7 +70,7 @@ impl TryFrom<StringToken> for String {
     }
 }
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
 pub enum Token {
     // Used for unit type variants in Enum. An "empty" enum is not represented as Enum<empty box>,
     // because this way we can have both unit and non-unit type variants.
diff --git a/packages/fuels-core/src/types/bech32.rs b/packages/fuels-core/src/types/bech32.rs
index 0ced1d959..56faf974e 100644
--- a/packages/fuels-core/src/types/bech32.rs
+++ b/packages/fuels-core/src/types/bech32.rs
@@ -3,8 +3,10 @@ use std::{
     str::FromStr,
 };
 
+use crate::types::Bits256;
 use bech32::{FromBase32, ToBase32, Variant::Bech32m};
-use fuel_tx::{Address, Bytes32, ContractId};
+use fuel_tx::{Address, Bytes32, ContractId, ContractIdExt};
+use fuel_types::AssetId;
 
 use crate::types::errors::{Error, Result};
 
@@ -128,6 +130,14 @@ impl From<ContractId> for Bech32ContractId {
     }
 }
 
+impl Bech32ContractId {
+    /// Creates an `AssetId` from the `Bech32ContractId` and `sub_id`.
+    pub fn asset_id(&self, sub_id: &Bits256) -> AssetId {
+        let sub_id = Bytes32::from(sub_id.0);
+        ContractId::from(self).asset_id(&sub_id)
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
diff --git a/packages/fuels-core/src/types/core/bits.rs b/packages/fuels-core/src/types/core/bits.rs
index 75234f723..8234232b6 100644
--- a/packages/fuels-core/src/types/core/bits.rs
+++ b/packages/fuels-core/src/types/core/bits.rs
@@ -1,3 +1,4 @@
+use fuel_types::AssetId;
 use fuels_macros::{Parameterize, Tokenizable, TryFrom};
 
 use crate::types::errors::{error, Error, Result};
@@ -9,6 +10,11 @@ use crate::types::errors::{error, Error, Result};
 pub struct Bits256(pub [u8; 32]);
 
 impl Bits256 {
+    /// Returns `Self` with zeroes inside.
+    pub fn zeroed() -> Self {
+        Self([0; 32])
+    }
+
     /// Create a new `Bits256` from a string representation of a hex.
     /// Accepts both `0x` prefixed and non-prefixed hex strings.
     pub fn from_hex_str(hex: &str) -> Result<Self> {
@@ -29,6 +35,12 @@ impl Bits256 {
     }
 }
 
+impl From<AssetId> for Bits256 {
+    fn from(value: AssetId) -> Self {
+        Self(value.into())
+    }
+}
+
 // A simple wrapper around [Bits256; 2] representing the `B512` type.
 #[derive(Debug, PartialEq, Eq, Copy, Clone, Parameterize, Tokenizable, TryFrom)]
 #[FuelsCorePath = "crate"]
diff --git a/packages/fuels-core/src/types/enum_variants.rs b/packages/fuels-core/src/types/enum_variants.rs
index cc7efeb06..ef532bd87 100644
--- a/packages/fuels-core/src/types/enum_variants.rs
+++ b/packages/fuels-core/src/types/enum_variants.rs
@@ -6,7 +6,7 @@ use crate::{
     },
 };
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 pub struct EnumVariants {
     param_types: Vec<ParamType>,
 }
diff --git a/packages/fuels-core/src/types/param_types.rs b/packages/fuels-core/src/types/param_types.rs
index fe4538f86..632e6d8a8 100644
--- a/packages/fuels-core/src/types/param_types.rs
+++ b/packages/fuels-core/src/types/param_types.rs
@@ -14,7 +14,7 @@ use crate::{
     },
 };
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 pub enum ParamType {
     U8,
     U16,
diff --git a/packages/fuels-core/src/utils/constants.rs b/packages/fuels-core/src/utils/constants.rs
index c189a6664..888005986 100644
--- a/packages/fuels-core/src/utils/constants.rs
+++ b/packages/fuels-core/src/utils/constants.rs
@@ -6,7 +6,7 @@ pub const WORD_SIZE: usize = core::mem::size_of::<Word>();
 
 // ANCHOR: default_tx_parameters
 pub const DEFAULT_GAS_PRICE: u64 = 0;
-pub const DEFAULT_GAS_LIMIT: u64 = 1_000_000;
+pub const DEFAULT_GAS_LIMIT: u64 = 100_000_000;
 pub const DEFAULT_MATURITY: u32 = 0;
 // ANCHOR_END: default_tx_parameters
 
diff --git a/packages/fuels-programs/src/logs.rs b/packages/fuels-programs/src/logs.rs
index 45a3d9e9e..0b3a9fdfa 100644
--- a/packages/fuels-programs/src/logs.rs
+++ b/packages/fuels-programs/src/logs.rs
@@ -179,7 +179,12 @@ impl<'a, I: Iterator<Item = &'a Receipt>> ExtractLogIdData for I {
     type Output = FilterMap<Self, fn(&Receipt) -> Option<(LogId, Vec<u8>)>>;
     fn extract_log_id_and_data(self) -> Self::Output {
         self.filter_map(|r| match r {
-            Receipt::LogData { rb, data, id, .. } => Some((LogId(*id, *rb), data.clone())),
+            Receipt::LogData {
+                rb,
+                data: Some(data),
+                id,
+                ..
+            } => Some((LogId(*id, *rb), data.clone())),
             Receipt::Log { ra, rb, id, .. } => Some((LogId(*id, *rb), ra.to_be_bytes().to_vec())),
             _ => None,
         })
diff --git a/packages/fuels-programs/src/receipt_parser.rs b/packages/fuels-programs/src/receipt_parser.rs
index 0b14b3665..3bdefff87 100644
--- a/packages/fuels-programs/src/receipt_parser.rs
+++ b/packages/fuels-programs/src/receipt_parser.rs
@@ -71,7 +71,12 @@ impl ReceiptParser {
 
     fn extract_return_data(&mut self, contract_id: &ContractId) -> Option<Vec<u8>> {
         for (index, receipt) in self.receipts.iter_mut().enumerate() {
-            if let Receipt::ReturnData { id, data, .. } = receipt {
+            if let Receipt::ReturnData {
+                id,
+                data: Some(data),
+                ..
+            } = receipt
+            {
                 if id == contract_id {
                     let data = std::mem::take(data);
                     self.receipts.remove(index);
@@ -134,10 +139,10 @@ impl ReceiptParser {
                     ..
                 },
             ) if *first_id == *contract_id
-                && !first_data.is_empty()
+                && first_data.is_some()
                 && *second_id == ContractId::zeroed() =>
             {
-                Some(vec_data)
+                vec_data.as_ref()
             }
             _ => None,
         }
@@ -176,7 +181,7 @@ mod tests {
             ptr: Default::default(),
             len: Default::default(),
             digest: Default::default(),
-            data: data.to_vec(),
+            data: Some(data.to_vec()),
             pc: Default::default(),
             is: Default::default(),
         }
diff --git a/packages/fuels/src/lib.rs b/packages/fuels/src/lib.rs
index 98fe9f1a3..2e8334914 100644
--- a/packages/fuels/src/lib.rs
+++ b/packages/fuels/src/lib.rs
@@ -14,8 +14,8 @@
 
 pub mod tx {
     pub use fuel_tx::{
-        field, Bytes32, ConsensusParameters, Receipt, Salt, ScriptExecutionResult, StorageSlot,
-        Transaction as FuelTransaction, TxId,
+        field, Bytes32, ConsensusParameters, ContractIdExt, Receipt, Salt, ScriptExecutionResult,
+        StorageSlot, Transaction as FuelTransaction, TxId,
     };
 }
 
diff --git a/packages/fuels/tests/bindings/sharing_types/contract_a/Forc.toml b/packages/fuels/tests/bindings/sharing_types/contract_a/Forc.toml
index 3044ac0e3..348af0004 100644
--- a/packages/fuels/tests/bindings/sharing_types/contract_a/Forc.toml
+++ b/packages/fuels/tests/bindings/sharing_types/contract_a/Forc.toml
@@ -6,3 +6,4 @@ name = "contract_a"
 
 [dependencies]
 shared_lib = { path = "../shared_lib" }
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/bindings/sharing_types/contract_b/Forc.toml b/packages/fuels/tests/bindings/sharing_types/contract_b/Forc.toml
index 99f9fbfd0..10af8dbb6 100644
--- a/packages/fuels/tests/bindings/sharing_types/contract_b/Forc.toml
+++ b/packages/fuels/tests/bindings/sharing_types/contract_b/Forc.toml
@@ -6,3 +6,4 @@ name = "contract_b"
 
 [dependencies]
 shared_lib = { path = "../shared_lib" }
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/bindings/sharing_types/shared_lib/Forc.toml b/packages/fuels/tests/bindings/sharing_types/shared_lib/Forc.toml
index a5107fb5f..9569a6424 100644
--- a/packages/fuels/tests/bindings/sharing_types/shared_lib/Forc.toml
+++ b/packages/fuels/tests/bindings/sharing_types/shared_lib/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "shared_lib"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/bindings/simple_contract/Forc.toml b/packages/fuels/tests/bindings/simple_contract/Forc.toml
index c0657fd85..df267c2a1 100644
--- a/packages/fuels/tests/bindings/simple_contract/Forc.toml
+++ b/packages/fuels/tests/bindings/simple_contract/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "simple_contract"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/bindings/type_paths/Forc.toml b/packages/fuels/tests/bindings/type_paths/Forc.toml
index f01d6008f..23a2d64a4 100644
--- a/packages/fuels/tests/bindings/type_paths/Forc.toml
+++ b/packages/fuels/tests/bindings/type_paths/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "type_paths"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts.rs b/packages/fuels/tests/contracts.rs
index abf5f1361..4a75bdf8a 100644
--- a/packages/fuels/tests/contracts.rs
+++ b/packages/fuels/tests/contracts.rs
@@ -280,7 +280,7 @@ async fn test_contract_call_fee_estimation() -> Result<()> {
     let tolerance = 0.2;
 
     let expected_min_gas_price = 0; // This is the default min_gas_price from the ConsensusParameters
-    let expected_gas_used = 598;
+    let expected_gas_used = 399;
     let expected_metered_bytes_size = 728;
     let expected_total_fee = 372;
 
@@ -620,7 +620,7 @@ async fn test_connect_wallet() -> Result<()> {
     // pay for call with wallet
     let tx_params = TxParameters::default()
         .set_gas_price(10)
-        .set_gas_limit(10000);
+        .set_gas_limit(1_000_000);
     contract_instance
         .methods()
         .initialize_counter(42)
@@ -661,7 +661,7 @@ async fn setup_output_variable_estimation_test(
     .deploy(&wallets[0], TxParameters::default())
     .await?;
 
-    let mint_asset_id = AssetId::from(*contract_id.hash());
+    let mint_asset_id = contract_id.asset_id(&Bits256::zeroed());
     let addresses: [Address; 3] = wallets
         .iter()
         .map(|wallet| wallet.address().into())
diff --git a/packages/fuels/tests/contracts/asserts/Forc.toml b/packages/fuels/tests/contracts/asserts/Forc.toml
index e6d8b1f23..9699ea950 100644
--- a/packages/fuels/tests/contracts/asserts/Forc.toml
+++ b/packages/fuels/tests/contracts/asserts/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "asserts"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/auth_testing_abi/Forc.toml b/packages/fuels/tests/contracts/auth_testing_abi/Forc.toml
index f306fecdf..46650f30a 100644
--- a/packages/fuels/tests/contracts/auth_testing_abi/Forc.toml
+++ b/packages/fuels/tests/contracts/auth_testing_abi/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "auth_testing_abi"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/auth_testing_contract/Forc.toml b/packages/fuels/tests/contracts/auth_testing_contract/Forc.toml
index 7ea22f673..d5d9fd2b3 100644
--- a/packages/fuels/tests/contracts/auth_testing_contract/Forc.toml
+++ b/packages/fuels/tests/contracts/auth_testing_contract/Forc.toml
@@ -5,5 +5,5 @@ license = "Apache-2.0"
 name = "auth_testing_contract"
 
 [dependencies]
-
 auth_testing_abi = { path = "../auth_testing_abi" }
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/block_timestamp/Forc.toml b/packages/fuels/tests/contracts/block_timestamp/Forc.toml
index e12e1261c..3ab556c8a 100644
--- a/packages/fuels/tests/contracts/block_timestamp/Forc.toml
+++ b/packages/fuels/tests/contracts/block_timestamp/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "block_timestamp"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/configurables/Forc.toml b/packages/fuels/tests/contracts/configurables/Forc.toml
index a1eda3c88..92f33c128 100644
--- a/packages/fuels/tests/contracts/configurables/Forc.toml
+++ b/packages/fuels/tests/contracts/configurables/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "configurables"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/contract_test/Forc.toml b/packages/fuels/tests/contracts/contract_test/Forc.toml
index 20e6c1ce4..7f175e460 100644
--- a/packages/fuels/tests/contracts/contract_test/Forc.toml
+++ b/packages/fuels/tests/contracts/contract_test/Forc.toml
@@ -6,3 +6,4 @@ name = "contract_test"
 
 [dependencies]
 increment_abi = { path = "../library_test", package = "library_test" }
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/large_return_data/Forc.toml b/packages/fuels/tests/contracts/large_return_data/Forc.toml
index 13e2a57c8..e9084460f 100644
--- a/packages/fuels/tests/contracts/large_return_data/Forc.toml
+++ b/packages/fuels/tests/contracts/large_return_data/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "large_return_data"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/lib_contract/Forc.toml b/packages/fuels/tests/contracts/lib_contract/Forc.toml
index 85ac32051..8d19a713e 100644
--- a/packages/fuels/tests/contracts/lib_contract/Forc.toml
+++ b/packages/fuels/tests/contracts/lib_contract/Forc.toml
@@ -6,3 +6,4 @@ name = "lib_contract"
 
 [dependencies]
 lib_contract = { path = "../lib_contract_abi/", package = "lib_contract_abi" }
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/lib_contract_abi/Forc.toml b/packages/fuels/tests/contracts/lib_contract_abi/Forc.toml
index 6b0c31acf..b75245dd1 100644
--- a/packages/fuels/tests/contracts/lib_contract_abi/Forc.toml
+++ b/packages/fuels/tests/contracts/lib_contract_abi/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "lib_contract_abi"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/lib_contract_caller/Forc.toml b/packages/fuels/tests/contracts/lib_contract_caller/Forc.toml
index 09b791984..31a86fcbd 100644
--- a/packages/fuels/tests/contracts/lib_contract_caller/Forc.toml
+++ b/packages/fuels/tests/contracts/lib_contract_caller/Forc.toml
@@ -6,3 +6,4 @@ name = "lib_contract_caller"
 
 [dependencies]
 lib_contract = { path = "../lib_contract_abi/", package = "lib_contract_abi" }
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/lib_contract_caller/src/main.sw b/packages/fuels/tests/contracts/lib_contract_caller/src/main.sw
index b1fe50eac..97dc615bd 100644
--- a/packages/fuels/tests/contracts/lib_contract_caller/src/main.sw
+++ b/packages/fuels/tests/contracts/lib_contract_caller/src/main.sw
@@ -2,6 +2,7 @@ contract;
 
 use lib_contract::LibContract;
 use std::token::mint_to_address;
+use std::constants::ZERO_B256;
 
 abi ContractCaller {
     fn increment_from_contract(contract_id: ContractId, value: u64) -> u64;
@@ -32,7 +33,7 @@ impl ContractCaller for Contract {
         let contract_instance = abi(LibContract, contract_id.into());
         let _ = contract_instance.increment(42);
 
-        mint_to_address(amount, address);
+        mint_to_address(address, ZERO_B256, amount);
     }
 
     fn require_from_contract(contract_id: ContractId) {
diff --git a/packages/fuels/tests/contracts/library_test/Forc.toml b/packages/fuels/tests/contracts/library_test/Forc.toml
index 65ff26b0d..82d9c2ace 100644
--- a/packages/fuels/tests/contracts/library_test/Forc.toml
+++ b/packages/fuels/tests/contracts/library_test/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "library_test"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/liquidity_pool/Forc.toml b/packages/fuels/tests/contracts/liquidity_pool/Forc.toml
index fcab2733d..069600dbb 100644
--- a/packages/fuels/tests/contracts/liquidity_pool/Forc.toml
+++ b/packages/fuels/tests/contracts/liquidity_pool/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "liquidity_pool"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/liquidity_pool/src/main.sw b/packages/fuels/tests/contracts/liquidity_pool/src/main.sw
index 667ccd6c0..e9a1e2b4a 100644
--- a/packages/fuels/tests/contracts/liquidity_pool/src/main.sw
+++ b/packages/fuels/tests/contracts/liquidity_pool/src/main.sw
@@ -11,6 +11,7 @@ use std::{
         transfer_to_address,
     },
 };
+use std::constants::ZERO_B256;
 
 abi LiquidityPool {
     #[payable]
@@ -24,25 +25,24 @@ const BASE_TOKEN: b256 = 0x9ae5b658754e096e4d681c548daf46354495a437cc61492599e33
 impl LiquidityPool for Contract {
     #[payable]
     fn deposit(recipient: Address) {
-        assert(ContractId::from(BASE_TOKEN) == msg_asset_id());
+        assert(BASE_TOKEN == msg_asset_id());
         assert(0 < msg_amount());
 
         // Mint two times the amount.
         let amount_to_mint = msg_amount() * 2;
 
         // Mint some LP token based upon the amount of the base token.
-        mint_to_address(amount_to_mint, recipient);
+        mint_to_address(recipient, ZERO_B256, amount_to_mint);
     }
 
     #[payable]
     fn withdraw(recipient: Address) {
-        assert(contract_id() == msg_asset_id());
         assert(0 < msg_amount());
 
         // Amount to withdraw.
         let amount_to_transfer = msg_amount() / 2;
 
         // Transfer base token to recipient.
-        transfer_to_address(amount_to_transfer, ContractId::from(BASE_TOKEN), recipient);
+        transfer_to_address(recipient, BASE_TOKEN, amount_to_transfer);
     }
 }
diff --git a/packages/fuels/tests/contracts/low_level_caller/Forc.toml b/packages/fuels/tests/contracts/low_level_caller/Forc.toml
index 72ce3f9bf..711f63503 100644
--- a/packages/fuels/tests/contracts/low_level_caller/Forc.toml
+++ b/packages/fuels/tests/contracts/low_level_caller/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "low_level_caller"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/msg_amount/Forc.toml b/packages/fuels/tests/contracts/msg_amount/Forc.toml
index 170eb174f..11e47a02f 100644
--- a/packages/fuels/tests/contracts/msg_amount/Forc.toml
+++ b/packages/fuels/tests/contracts/msg_amount/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "msg_amount"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/multiple_read_calls/Forc.toml b/packages/fuels/tests/contracts/multiple_read_calls/Forc.toml
index c0293c3bf..40aae52b9 100644
--- a/packages/fuels/tests/contracts/multiple_read_calls/Forc.toml
+++ b/packages/fuels/tests/contracts/multiple_read_calls/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "multiple_read_calls"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/payable_annotation/Forc.toml b/packages/fuels/tests/contracts/payable_annotation/Forc.toml
index 66183feeb..c0e871fe7 100644
--- a/packages/fuels/tests/contracts/payable_annotation/Forc.toml
+++ b/packages/fuels/tests/contracts/payable_annotation/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "payable_annotation"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/require/Forc.toml b/packages/fuels/tests/contracts/require/Forc.toml
index cc27a685e..9f5f13899 100644
--- a/packages/fuels/tests/contracts/require/Forc.toml
+++ b/packages/fuels/tests/contracts/require/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "require"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/revert_transaction_error/Forc.toml b/packages/fuels/tests/contracts/revert_transaction_error/Forc.toml
index 9b2ef69e6..75071654b 100644
--- a/packages/fuels/tests/contracts/revert_transaction_error/Forc.toml
+++ b/packages/fuels/tests/contracts/revert_transaction_error/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "revert_transaction_error"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/storage/Forc.toml b/packages/fuels/tests/contracts/storage/Forc.toml
index e302196a2..d3adc9cd0 100644
--- a/packages/fuels/tests/contracts/storage/Forc.toml
+++ b/packages/fuels/tests/contracts/storage/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "storage"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/token_ops/Forc.toml b/packages/fuels/tests/contracts/token_ops/Forc.toml
index 5c8f0db95..ddc85d2af 100644
--- a/packages/fuels/tests/contracts/token_ops/Forc.toml
+++ b/packages/fuels/tests/contracts/token_ops/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "token_ops"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/token_ops/src/main.sw b/packages/fuels/tests/contracts/token_ops/src/main.sw
index a8aa018a0..542c666fe 100644
--- a/packages/fuels/tests/contracts/token_ops/src/main.sw
+++ b/packages/fuels/tests/contracts/token_ops/src/main.sw
@@ -1,14 +1,15 @@
 contract;
 
 use std::{bytes::Bytes, context::balance_of, context::msg_amount, message::send_message, token::*};
+use std::constants::ZERO_B256;
 
 abi TestFuelCoin {
     fn mint_coins(mint_amount: u64);
     fn mint_to_addresses(mint_amount: u64, addresses: [Address; 3]);
     fn burn_coins(burn_amount: u64);
-    fn force_transfer_coins(coins: u64, asset_id: ContractId, target: ContractId);
-    fn transfer_coins_to_output(coins: u64, asset_id: ContractId, recipient: Address);
-    fn get_balance(target: ContractId, asset_id: ContractId) -> u64;
+    fn force_transfer_coins(coins: u64, asset_id: AssetId, target: ContractId);
+    fn transfer_coins_to_output(coins: u64, asset_id: AssetId, recipient: Address);
+    fn get_balance(target: ContractId, asset_id: AssetId) -> u64;
     #[payable]
     fn get_msg_amount() -> u64;
     fn send_message(recipient: b256, coins: u64);
@@ -16,30 +17,30 @@ abi TestFuelCoin {
 
 impl TestFuelCoin for Contract {
     fn mint_coins(mint_amount: u64) {
-        mint(mint_amount);
+        mint(ZERO_B256, mint_amount);
     }
     fn mint_to_addresses(mint_amount: u64, addresses: [Address; 3]) {
         let mut counter = 0;
         while counter < 3 {
-            mint_to_address(mint_amount, addresses[counter]);
+            mint_to_address(addresses[counter], ZERO_B256, mint_amount);
             counter = counter + 1;
         }
     }
 
     fn burn_coins(burn_amount: u64) {
-        burn(burn_amount);
+        burn(ZERO_B256, burn_amount);
     }
 
-    fn force_transfer_coins(coins: u64, asset_id: ContractId, target: ContractId) {
-        force_transfer_to_contract(coins, asset_id, target);
+    fn force_transfer_coins(coins: u64, asset_id: AssetId, target: ContractId) {
+        force_transfer_to_contract(target, asset_id, coins);
     }
 
     // ANCHOR: variable_outputs
-    fn transfer_coins_to_output(coins: u64, asset_id: ContractId, recipient: Address) {
-        transfer_to_address(coins, asset_id, recipient);
+    fn transfer_coins_to_output(coins: u64, asset_id: AssetId, recipient: Address) {
+        transfer_to_address(recipient, asset_id, coins);
     }
     // ANCHOR_END: variable_outputs
-    fn get_balance(target: ContractId, asset_id: ContractId) -> u64 {
+    fn get_balance(target: ContractId, asset_id: AssetId) -> u64 {
         balance_of(target, asset_id)
     }
 
diff --git a/packages/fuels/tests/contracts/transaction_block_height/Forc.toml b/packages/fuels/tests/contracts/transaction_block_height/Forc.toml
index 2f744a0f3..88f4d951a 100644
--- a/packages/fuels/tests/contracts/transaction_block_height/Forc.toml
+++ b/packages/fuels/tests/contracts/transaction_block_height/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "transaction_block_height"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/contracts/transaction_block_height/src/main.sw b/packages/fuels/tests/contracts/transaction_block_height/src/main.sw
index 352b83b94..eff42e87e 100644
--- a/packages/fuels/tests/contracts/transaction_block_height/src/main.sw
+++ b/packages/fuels/tests/contracts/transaction_block_height/src/main.sw
@@ -1,12 +1,12 @@
 contract;
 
 abi MyContract {
-    fn get_current_height() -> u64;
+    fn get_current_height() -> u32;
     fn calling_this_will_produce_a_block();
 }
 
 impl MyContract for Contract {
-    fn get_current_height() -> u64 {
+    fn get_current_height() -> u32 {
         std::block::height()
     }
 
diff --git a/packages/fuels/tests/logs.rs b/packages/fuels/tests/logs.rs
index 1bdd9ce5e..c203c481d 100644
--- a/packages/fuels/tests/logs.rs
+++ b/packages/fuels/tests/logs.rs
@@ -1244,10 +1244,11 @@ async fn contract_token_ops_error_messages() -> Result<()> {
 
     {
         let contract_id = contract_instance.contract_id();
+        let asset_id = contract_id.asset_id(&Bits256::zeroed()).into();
         let address = wallet.address();
 
         let error = contract_methods
-            .transfer_coins_to_output(1_000_000, contract_id, address)
+            .transfer_coins_to_output(1_000_000, asset_id, address)
             .call()
             .await
             .expect_err("should return a revert error");
diff --git a/packages/fuels/tests/logs/contract_logs/Forc.toml b/packages/fuels/tests/logs/contract_logs/Forc.toml
index 0fce1449d..76efbd74a 100644
--- a/packages/fuels/tests/logs/contract_logs/Forc.toml
+++ b/packages/fuels/tests/logs/contract_logs/Forc.toml
@@ -6,3 +6,4 @@ name = "contract_logs"
 
 [dependencies]
 contract_logs = { path = "../contract_logs_abi/", package = "contract_logs_abi" }
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/logs/contract_logs_abi/Forc.toml b/packages/fuels/tests/logs/contract_logs_abi/Forc.toml
index 17abdcce8..53dac61af 100644
--- a/packages/fuels/tests/logs/contract_logs_abi/Forc.toml
+++ b/packages/fuels/tests/logs/contract_logs_abi/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "contract_logs_abi"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/logs/contract_with_contract_logs/Forc.toml b/packages/fuels/tests/logs/contract_with_contract_logs/Forc.toml
index 8b0798fac..6ec4d54f5 100644
--- a/packages/fuels/tests/logs/contract_with_contract_logs/Forc.toml
+++ b/packages/fuels/tests/logs/contract_with_contract_logs/Forc.toml
@@ -6,3 +6,4 @@ name = "contract_with_contract_logs"
 
 [dependencies]
 library = { path = "../contract_logs_abi/", package = "contract_logs_abi" }
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/logs/script_logs/Forc.toml b/packages/fuels/tests/logs/script_logs/Forc.toml
index cacd8d3dd..4d0b025b4 100644
--- a/packages/fuels/tests/logs/script_logs/Forc.toml
+++ b/packages/fuels/tests/logs/script_logs/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_logs"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/logs/script_with_contract_logs/Forc.toml b/packages/fuels/tests/logs/script_with_contract_logs/Forc.toml
index 56b09e02f..cf828dadd 100644
--- a/packages/fuels/tests/logs/script_with_contract_logs/Forc.toml
+++ b/packages/fuels/tests/logs/script_with_contract_logs/Forc.toml
@@ -6,3 +6,4 @@ name = "script_with_contract_logs"
 
 [dependencies]
 library = { path = "../contract_logs_abi/", package = "contract_logs_abi" }
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/predicates.rs b/packages/fuels/tests/predicates.rs
index c5bd35e77..97c3912fa 100644
--- a/packages/fuels/tests/predicates.rs
+++ b/packages/fuels/tests/predicates.rs
@@ -221,7 +221,7 @@ async fn pay_with_predicate() -> Result<()> {
     .await?;
 
     let contract_methods = MyContract::new(contract_id.clone(), predicate.clone()).methods();
-    let tx_params = TxParameters::new(1000000, 10000, 0);
+    let tx_params = TxParameters::new(1, 1000000, 0);
 
     assert_eq!(predicate.get_asset_balance(&BASE_ASSET_ID).await?, 192);
 
@@ -232,7 +232,7 @@ async fn pay_with_predicate() -> Result<()> {
         .await?;
 
     assert_eq!(42, response.value);
-    assert_eq!(predicate.get_asset_balance(&BASE_ASSET_ID).await?, 187);
+    assert_eq!(predicate.get_asset_balance(&BASE_ASSET_ID).await?, 191);
 
     Ok(())
 }
@@ -275,8 +275,8 @@ async fn pay_with_predicate_vector_data() -> Result<()> {
 
     let contract_methods = MyContract::new(contract_id.clone(), predicate.clone()).methods();
     let tx_params = TxParameters::default()
-        .set_gas_price(100000)
-        .set_gas_limit(10000);
+        .set_gas_price(1)
+        .set_gas_limit(1000000);
 
     assert_eq!(predicate.get_asset_balance(&BASE_ASSET_ID).await?, 192);
 
@@ -287,7 +287,7 @@ async fn pay_with_predicate_vector_data() -> Result<()> {
         .await?;
 
     assert_eq!(42, response.value);
-    assert_eq!(predicate.get_asset_balance(&BASE_ASSET_ID).await?, 190);
+    assert_eq!(predicate.get_asset_balance(&BASE_ASSET_ID).await?, 191);
 
     Ok(())
 }
@@ -521,7 +521,7 @@ async fn contract_tx_and_call_params_with_predicate() -> Result<()> {
     println!("Contract deployed @ {contract_id}");
     let contract_methods = MyContract::new(contract_id.clone(), predicate.clone()).methods();
 
-    let my_tx_params = TxParameters::default().set_gas_price(100);
+    let my_tx_params = TxParameters::default().set_gas_price(1);
 
     let call_params_amount = 100;
     let call_params = CallParameters::default()
diff --git a/packages/fuels/tests/predicates/basic_predicate/Forc.toml b/packages/fuels/tests/predicates/basic_predicate/Forc.toml
index 06d368ee4..c6fbebefa 100644
--- a/packages/fuels/tests/predicates/basic_predicate/Forc.toml
+++ b/packages/fuels/tests/predicates/basic_predicate/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "basic_predicate"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/predicates/basic_predicate/src/main.sw b/packages/fuels/tests/predicates/basic_predicate/src/main.sw
index a9ff6dd6d..ba1cc464c 100644
--- a/packages/fuels/tests/predicates/basic_predicate/src/main.sw
+++ b/packages/fuels/tests/predicates/basic_predicate/src/main.sw
@@ -1,5 +1,5 @@
 predicate;
 
 fn main(a: u32, b: u64) -> bool {
-    b == a
+    b == a.as_u64()
 }
diff --git a/packages/fuels/tests/predicates/predicate_configurables/Forc.toml b/packages/fuels/tests/predicates/predicate_configurables/Forc.toml
index 853bfd837..f03b71d32 100644
--- a/packages/fuels/tests/predicates/predicate_configurables/Forc.toml
+++ b/packages/fuels/tests/predicates/predicate_configurables/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "predicate_configurables"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/predicates/signatures/Forc.toml b/packages/fuels/tests/predicates/signatures/Forc.toml
index 51883a82a..7ae718555 100644
--- a/packages/fuels/tests/predicates/signatures/Forc.toml
+++ b/packages/fuels/tests/predicates/signatures/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "signatures"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/providers.rs b/packages/fuels/tests/providers.rs
index d235d78df..8f85a80f0 100644
--- a/packages/fuels/tests/providers.rs
+++ b/packages/fuels/tests/providers.rs
@@ -11,6 +11,7 @@ use fuels::{
     tx::Receipt,
     types::{block::Block, coin_type::CoinType, errors::error, message::Message},
 };
+use fuels_core::types::Bits256;
 
 #[tokio::test]
 async fn test_provider_launch_and_connect() -> Result<()> {
@@ -337,6 +338,8 @@ async fn test_gas_forwarded_defaults_to_tx_limit() -> Result<()> {
         ),
     );
 
+    // The gas used by the script to call a contract and forward remaining gas limit.
+    let gas_used_by_script = 161;
     let gas_limit = 225_883;
     let response = contract_instance
         .methods()
@@ -353,7 +356,7 @@ async fn test_gas_forwarded_defaults_to_tx_limit() -> Result<()> {
         .gas()
         .unwrap();
 
-    assert_eq!(gas_limit, gas_forwarded);
+    assert_eq!(gas_limit, gas_forwarded + gas_used_by_script);
 
     Ok(())
 }
@@ -374,9 +377,10 @@ async fn test_amount_and_asset_forwarding() -> Result<()> {
     );
     let contract_id = contract_instance.contract_id();
     let contract_methods = contract_instance.methods();
+    let asset_id = contract_id.asset_id(&Bits256::zeroed()).into();
 
     let mut balance_response = contract_methods
-        .get_balance(contract_id, contract_id)
+        .get_balance(contract_id, asset_id)
         .call()
         .await?;
     assert_eq!(balance_response.value, 0);
@@ -384,7 +388,7 @@ async fn test_amount_and_asset_forwarding() -> Result<()> {
     contract_methods.mint_coins(5_000_000).call().await?;
 
     balance_response = contract_methods
-        .get_balance(contract_id, contract_id)
+        .get_balance(contract_id, asset_id)
         .call()
         .await?;
     assert_eq!(balance_response.value, 5_000_000);
@@ -417,7 +421,7 @@ async fn test_amount_and_asset_forwarding() -> Result<()> {
 
     // withdraw some tokens to wallet
     contract_methods
-        .transfer_coins_to_output(1_000_000, contract_id, address)
+        .transfer_coins_to_output(1_000_000, asset_id, address)
         .append_variable_outputs(1)
         .call()
         .await?;
@@ -534,7 +538,7 @@ async fn test_call_param_gas_errors() -> Result<()> {
     let contract_methods = contract_instance.methods();
     let response = contract_methods
         .initialize_counter(42)
-        .tx_params(TxParameters::default().set_gas_limit(3000))
+        .tx_params(TxParameters::default().set_gas_limit(446000))
         .call_params(CallParameters::default().set_gas_forwarded(1))?
         .call()
         .await
diff --git a/packages/fuels/tests/scripts.rs b/packages/fuels/tests/scripts.rs
index 3bb7cb6c3..884dd768b 100644
--- a/packages/fuels/tests/scripts.rs
+++ b/packages/fuels/tests/scripts.rs
@@ -135,7 +135,7 @@ async fn test_basic_script_with_tx_parameters() -> Result<()> {
     // ANCHOR: script_with_tx_params
     let parameters = TxParameters::default()
         .set_gas_price(1)
-        .set_gas_limit(10_000);
+        .set_gas_limit(1_000_000);
     let result = script_instance
         .main(a, b)
         .tx_params(parameters)
@@ -247,8 +247,8 @@ async fn test_output_variable_estimation() -> Result<()> {
     receiver.set_provider(provider);
 
     let amount = 1000;
-    let asset_id = ContractId::from(*BASE_ASSET_ID);
-    let script_call = script_instance.main(amount, asset_id, receiver.address());
+    let asset_id = BASE_ASSET_ID;
+    let script_call = script_instance.main(amount, asset_id.into(), receiver.address());
     let inputs = wallet
         .get_asset_inputs_for_amount(BASE_ASSET_ID, amount, None)
         .await?;
diff --git a/packages/fuels/tests/scripts/arguments/Forc.toml b/packages/fuels/tests/scripts/arguments/Forc.toml
index f15bbe45f..e688700f9 100644
--- a/packages/fuels/tests/scripts/arguments/Forc.toml
+++ b/packages/fuels/tests/scripts/arguments/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "arguments"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/scripts/basic_script/Forc.toml b/packages/fuels/tests/scripts/basic_script/Forc.toml
index 32c24fc81..5d1375951 100644
--- a/packages/fuels/tests/scripts/basic_script/Forc.toml
+++ b/packages/fuels/tests/scripts/basic_script/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "basic_script"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/scripts/basic_script/src/main.sw b/packages/fuels/tests/scripts/basic_script/src/main.sw
index 6302d4a8e..b4da60172 100644
--- a/packages/fuels/tests/scripts/basic_script/src/main.sw
+++ b/packages/fuels/tests/scripts/basic_script/src/main.sw
@@ -1,7 +1,7 @@
 script;
 
 fn main(a: u64, b: u32) -> str[5] {
-    if a < b {
+    if a < b.as_u64() {
         let my_string: str[5] = "hello";
         my_string
     } else {
diff --git a/packages/fuels/tests/scripts/require_from_contract/Forc.toml b/packages/fuels/tests/scripts/require_from_contract/Forc.toml
index 8bb8ee1a8..f3556040b 100644
--- a/packages/fuels/tests/scripts/require_from_contract/Forc.toml
+++ b/packages/fuels/tests/scripts/require_from_contract/Forc.toml
@@ -6,3 +6,4 @@ name = "require_from_contract"
 
 [dependencies]
 library = { path = "../../contracts/lib_contract_abi", package = "lib_contract_abi" }
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/scripts/script_array/Forc.toml b/packages/fuels/tests/scripts/script_array/Forc.toml
index 03c93b8f5..bad5d9c72 100644
--- a/packages/fuels/tests/scripts/script_array/Forc.toml
+++ b/packages/fuels/tests/scripts/script_array/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_array"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/scripts/script_asserts/Forc.toml b/packages/fuels/tests/scripts/script_asserts/Forc.toml
index 3a5691596..e0f1080e2 100644
--- a/packages/fuels/tests/scripts/script_asserts/Forc.toml
+++ b/packages/fuels/tests/scripts/script_asserts/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_asserts"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/scripts/script_b256/Forc.toml b/packages/fuels/tests/scripts/script_b256/Forc.toml
index 7f1f12e40..1f5db8d5d 100644
--- a/packages/fuels/tests/scripts/script_b256/Forc.toml
+++ b/packages/fuels/tests/scripts/script_b256/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_b256"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/scripts/script_configurables/Forc.toml b/packages/fuels/tests/scripts/script_configurables/Forc.toml
index acf0005e9..c5edc0e28 100644
--- a/packages/fuels/tests/scripts/script_configurables/Forc.toml
+++ b/packages/fuels/tests/scripts/script_configurables/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_configurables"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/scripts/script_enum/Forc.toml b/packages/fuels/tests/scripts/script_enum/Forc.toml
index f4941d428..2172ab275 100644
--- a/packages/fuels/tests/scripts/script_enum/Forc.toml
+++ b/packages/fuels/tests/scripts/script_enum/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_enum"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/scripts/script_require/Forc.toml b/packages/fuels/tests/scripts/script_require/Forc.toml
index ae05b728f..4b4a88921 100644
--- a/packages/fuels/tests/scripts/script_require/Forc.toml
+++ b/packages/fuels/tests/scripts/script_require/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_require"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/scripts/script_struct/Forc.toml b/packages/fuels/tests/scripts/script_struct/Forc.toml
index 165e1c61a..2be65dc43 100644
--- a/packages/fuels/tests/scripts/script_struct/Forc.toml
+++ b/packages/fuels/tests/scripts/script_struct/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_struct"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/scripts/transfer_script/Forc.toml b/packages/fuels/tests/scripts/transfer_script/Forc.toml
index 68199fabf..336d7c399 100644
--- a/packages/fuels/tests/scripts/transfer_script/Forc.toml
+++ b/packages/fuels/tests/scripts/transfer_script/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "transfer_script"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/scripts/transfer_script/src/main.sw b/packages/fuels/tests/scripts/transfer_script/src/main.sw
index 337e30813..2366121d2 100644
--- a/packages/fuels/tests/scripts/transfer_script/src/main.sw
+++ b/packages/fuels/tests/scripts/transfer_script/src/main.sw
@@ -2,6 +2,6 @@ script;
 
 use std::token::transfer_to_address;
 
-fn main(amount: u64, asset: ContractId, receiver: Address) -> () {
-    transfer_to_address(amount, asset, receiver);
+fn main(amount: u64, asset: AssetId, receiver: Address) -> () {
+    transfer_to_address(receiver, asset, amount);
 }
diff --git a/packages/fuels/tests/types/contracts/b512/Forc.toml b/packages/fuels/tests/types/contracts/b512/Forc.toml
index acb7c4b21..7ef51cc9c 100644
--- a/packages/fuels/tests/types/contracts/b512/Forc.toml
+++ b/packages/fuels/tests/types/contracts/b512/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "b512"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/bytes/Forc.toml b/packages/fuels/tests/types/contracts/bytes/Forc.toml
index 57958b02d..d6111f8f6 100644
--- a/packages/fuels/tests/types/contracts/bytes/Forc.toml
+++ b/packages/fuels/tests/types/contracts/bytes/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "bytes"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/call_empty_return/Forc.toml b/packages/fuels/tests/types/contracts/call_empty_return/Forc.toml
index 9782a12f9..9fd6b5d88 100644
--- a/packages/fuels/tests/types/contracts/call_empty_return/Forc.toml
+++ b/packages/fuels/tests/types/contracts/call_empty_return/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "call_empty_return"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/complex_types_contract/Forc.toml b/packages/fuels/tests/types/contracts/complex_types_contract/Forc.toml
index 1528f7adb..6ba4973cc 100644
--- a/packages/fuels/tests/types/contracts/complex_types_contract/Forc.toml
+++ b/packages/fuels/tests/types/contracts/complex_types_contract/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "complex_types_contract"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/contract_output_test/Forc.toml b/packages/fuels/tests/types/contracts/contract_output_test/Forc.toml
index fc60a1b05..356b036ac 100644
--- a/packages/fuels/tests/types/contracts/contract_output_test/Forc.toml
+++ b/packages/fuels/tests/types/contracts/contract_output_test/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "contract_output_test"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/empty_arguments/Forc.toml b/packages/fuels/tests/types/contracts/empty_arguments/Forc.toml
index cc1182616..64059cc3a 100644
--- a/packages/fuels/tests/types/contracts/empty_arguments/Forc.toml
+++ b/packages/fuels/tests/types/contracts/empty_arguments/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "empty_arguments"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/enum_as_input/Forc.toml b/packages/fuels/tests/types/contracts/enum_as_input/Forc.toml
index dffb513cc..47311ae22 100644
--- a/packages/fuels/tests/types/contracts/enum_as_input/Forc.toml
+++ b/packages/fuels/tests/types/contracts/enum_as_input/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "enum_as_input"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/enum_encoding/Forc.toml b/packages/fuels/tests/types/contracts/enum_encoding/Forc.toml
index 688f05519..71b1ab0a4 100644
--- a/packages/fuels/tests/types/contracts/enum_encoding/Forc.toml
+++ b/packages/fuels/tests/types/contracts/enum_encoding/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "enum_encoding"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/enum_inside_struct/Forc.toml b/packages/fuels/tests/types/contracts/enum_inside_struct/Forc.toml
index f09effbc0..2b1c7a139 100644
--- a/packages/fuels/tests/types/contracts/enum_inside_struct/Forc.toml
+++ b/packages/fuels/tests/types/contracts/enum_inside_struct/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "enum_inside_struct"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/evm_address/Forc.toml b/packages/fuels/tests/types/contracts/evm_address/Forc.toml
index af826f8d9..42b762a01 100644
--- a/packages/fuels/tests/types/contracts/evm_address/Forc.toml
+++ b/packages/fuels/tests/types/contracts/evm_address/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "evm_address"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/generics/Forc.toml b/packages/fuels/tests/types/contracts/generics/Forc.toml
index 258e92faf..f1ddcc371 100644
--- a/packages/fuels/tests/types/contracts/generics/Forc.toml
+++ b/packages/fuels/tests/types/contracts/generics/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "generics"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/identity/Forc.toml b/packages/fuels/tests/types/contracts/identity/Forc.toml
index ad18bc27f..5c67218c6 100644
--- a/packages/fuels/tests/types/contracts/identity/Forc.toml
+++ b/packages/fuels/tests/types/contracts/identity/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "identity"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/native_types/Forc.toml b/packages/fuels/tests/types/contracts/native_types/Forc.toml
index 0be1771e5..9e5db4fd5 100644
--- a/packages/fuels/tests/types/contracts/native_types/Forc.toml
+++ b/packages/fuels/tests/types/contracts/native_types/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "native_types"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/nested_structs/Forc.toml b/packages/fuels/tests/types/contracts/nested_structs/Forc.toml
index cc6fa4e8e..f64e32903 100644
--- a/packages/fuels/tests/types/contracts/nested_structs/Forc.toml
+++ b/packages/fuels/tests/types/contracts/nested_structs/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "nested_structs"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/options/Forc.toml b/packages/fuels/tests/types/contracts/options/Forc.toml
index 4b0808785..06d370ce4 100644
--- a/packages/fuels/tests/types/contracts/options/Forc.toml
+++ b/packages/fuels/tests/types/contracts/options/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "options"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/raw_slice/Forc.toml b/packages/fuels/tests/types/contracts/raw_slice/Forc.toml
index 4d0cc8264..143b0d72e 100644
--- a/packages/fuels/tests/types/contracts/raw_slice/Forc.toml
+++ b/packages/fuels/tests/types/contracts/raw_slice/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "raw_slice"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/results/Forc.toml b/packages/fuels/tests/types/contracts/results/Forc.toml
index 7f469f5d7..26bc53b9f 100644
--- a/packages/fuels/tests/types/contracts/results/Forc.toml
+++ b/packages/fuels/tests/types/contracts/results/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "results"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/std_lib_string/Forc.toml b/packages/fuels/tests/types/contracts/std_lib_string/Forc.toml
index db2113c44..f92da038f 100644
--- a/packages/fuels/tests/types/contracts/std_lib_string/Forc.toml
+++ b/packages/fuels/tests/types/contracts/std_lib_string/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "std_lib_string"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/str_in_array/Forc.toml b/packages/fuels/tests/types/contracts/str_in_array/Forc.toml
index 45cf1941b..bc4cd810c 100644
--- a/packages/fuels/tests/types/contracts/str_in_array/Forc.toml
+++ b/packages/fuels/tests/types/contracts/str_in_array/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "str_in_array"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/tuples/Forc.toml b/packages/fuels/tests/types/contracts/tuples/Forc.toml
index 14e440aec..3d77759cd 100644
--- a/packages/fuels/tests/types/contracts/tuples/Forc.toml
+++ b/packages/fuels/tests/types/contracts/tuples/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "tuples"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/two_structs/Forc.toml b/packages/fuels/tests/types/contracts/two_structs/Forc.toml
index 07ff3ac96..90ed5bf30 100644
--- a/packages/fuels/tests/types/contracts/two_structs/Forc.toml
+++ b/packages/fuels/tests/types/contracts/two_structs/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "two_structs"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/type_inside_enum/Forc.toml b/packages/fuels/tests/types/contracts/type_inside_enum/Forc.toml
index d467f8ebc..ba0ab4b9d 100644
--- a/packages/fuels/tests/types/contracts/type_inside_enum/Forc.toml
+++ b/packages/fuels/tests/types/contracts/type_inside_enum/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "type_inside_enum"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/u128/Forc.toml b/packages/fuels/tests/types/contracts/u128/Forc.toml
index 7c088696a..ec950b090 100644
--- a/packages/fuels/tests/types/contracts/u128/Forc.toml
+++ b/packages/fuels/tests/types/contracts/u128/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "u128"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/u256/Forc.toml b/packages/fuels/tests/types/contracts/u256/Forc.toml
index 31818ffda..95351c0cb 100644
--- a/packages/fuels/tests/types/contracts/u256/Forc.toml
+++ b/packages/fuels/tests/types/contracts/u256/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "u256"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/vector_output/Forc.toml b/packages/fuels/tests/types/contracts/vector_output/Forc.toml
index 0d7f08dad..ec901a9e9 100644
--- a/packages/fuels/tests/types/contracts/vector_output/Forc.toml
+++ b/packages/fuels/tests/types/contracts/vector_output/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "vector_output"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/vectors/Forc.toml b/packages/fuels/tests/types/contracts/vectors/Forc.toml
index 39c4ced3d..c71c44c25 100644
--- a/packages/fuels/tests/types/contracts/vectors/Forc.toml
+++ b/packages/fuels/tests/types/contracts/vectors/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "vectors"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/contracts/vectors/src/main.sw b/packages/fuels/tests/types/contracts/vectors/src/main.sw
index 7cb28649d..a42ed5c7a 100644
--- a/packages/fuels/tests/types/contracts/vectors/src/main.sw
+++ b/packages/fuels/tests/types/contracts/vectors/src/main.sw
@@ -26,15 +26,15 @@ abi MyContract {
 
 impl MyContract for Contract {
     fn u32_vec(arg: Vec<u32>) {
-        let expected = vec_from([0u8, 1u8, 2u8]);
+        let expected = vec_from([0, 1, 2]);
 
         assert(arg == expected);
     }
 
     fn vec_in_vec(arg: Vec<Vec<u32>>) {
         let mut expected = Vec::new();
-        expected.push(vec_from([0u8, 1u8, 2u8]));
-        expected.push(vec_from([0u8, 1u8, 2u8]));
+        expected.push(vec_from([0, 1, 2]));
+        expected.push(vec_from([0, 1, 2]));
 
         assert(expected == arg);
     }
@@ -48,7 +48,7 @@ impl MyContract for Contract {
     }
     fn vec_in_struct(arg: SomeStruct<Vec<u32>>) {
         let expected = SomeStruct {
-            a: vec_from([0u8, 1u8, 2u8]),
+            a: vec_from([0, 1, 2]),
         };
 
         assert(arg.a == expected.a);
@@ -62,13 +62,13 @@ impl MyContract for Contract {
     }
 
     fn vec_in_array(arg: [Vec<u32>; 2]) {
-        let expected = [vec_from([0u8, 1u8, 2u8]), vec_from([0u8, 1u8, 2u8])];
+        let expected = [vec_from([0, 1, 2]), vec_from([0, 1, 2])];
 
         assert(expected == arg);
     }
 
     fn vec_in_enum(arg: SomeEnum<Vec<u32>>) {
-        let vec = vec_from([0u8, 1u8, 2u8]);
+        let vec = vec_from([0, 1, 2]);
         let expected = SomeEnum::a(vec);
 
         assert(expected == arg);
@@ -90,7 +90,7 @@ impl MyContract for Contract {
     }
 
     fn vec_in_tuple(arg: (Vec<u32>, Vec<u32>)) {
-        let expected = (vec_from([0u8, 1u8, 2u8]), vec_from([0u8, 1u8, 2u8]));
+        let expected = (vec_from([0, 1, 2]), vec_from([0, 1, 2]));
 
         assert(arg == expected);
     }
@@ -99,20 +99,20 @@ impl MyContract for Contract {
 
         let mut inner_vec_1 = Vec::new();
 
-        let inner_inner_vec_1 = vec_from([0u8, 1u8, 2u8]);
+        let inner_inner_vec_1 = vec_from([0, 1, 2]);
         inner_vec_1.push(inner_inner_vec_1);
 
-        let inner_inner_vec_2 = vec_from([3u8, 4u8, 5u8]);
+        let inner_inner_vec_2 = vec_from([3, 4, 5]);
         inner_vec_1.push(inner_inner_vec_2);
 
         expected.push(SomeStruct { a: inner_vec_1 });
 
         let mut inner_vec_2 = Vec::new();
 
-        let inner_inner_vec_3 = vec_from([6u8, 7u8, 8u8]);
+        let inner_inner_vec_3 = vec_from([6, 7, 8]);
         inner_vec_2.push(inner_inner_vec_3);
 
-        let inner_inner_vec_4 = vec_from([9u8, 10u8, 11u8]);
+        let inner_inner_vec_4 = vec_from([9, 10, 11]);
         inner_vec_2.push(inner_inner_vec_4);
 
         expected.push(SomeStruct { a: inner_vec_2 });
diff --git a/packages/fuels/tests/types/predicates/address/Forc.toml b/packages/fuels/tests/types/predicates/address/Forc.toml
index 66b3b6cf0..6e9ccd1c6 100644
--- a/packages/fuels/tests/types/predicates/address/Forc.toml
+++ b/packages/fuels/tests/types/predicates/address/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "address"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/enums/Forc.toml b/packages/fuels/tests/types/predicates/enums/Forc.toml
index d056e3a33..60af6a008 100644
--- a/packages/fuels/tests/types/predicates/enums/Forc.toml
+++ b/packages/fuels/tests/types/predicates/enums/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "enums"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/predicate_bytes/Forc.toml b/packages/fuels/tests/types/predicates/predicate_bytes/Forc.toml
index 04b33b007..a75a8ea5e 100644
--- a/packages/fuels/tests/types/predicates/predicate_bytes/Forc.toml
+++ b/packages/fuels/tests/types/predicates/predicate_bytes/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "predicate_bytes"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/predicate_generics/Forc.toml b/packages/fuels/tests/types/predicates/predicate_generics/Forc.toml
index 3f72203ca..9cccb98b4 100644
--- a/packages/fuels/tests/types/predicates/predicate_generics/Forc.toml
+++ b/packages/fuels/tests/types/predicates/predicate_generics/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "predicate_generics"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/predicate_generics/src/main.sw b/packages/fuels/tests/types/predicates/predicate_generics/src/main.sw
index 9f298fd7c..6e5a93734 100644
--- a/packages/fuels/tests/types/predicates/predicate_generics/src/main.sw
+++ b/packages/fuels/tests/types/predicates/predicate_generics/src/main.sw
@@ -15,7 +15,7 @@ fn main(
     generic_enum: GenericEnum<u16, u32>,
 ) -> bool {
     if let GenericEnum::Generic(other_struct) = generic_enum {
-        return other_struct.value == generic_struct.value;
+        return other_struct.value == generic_struct.value.as_u16();
     }
 
     false
diff --git a/packages/fuels/tests/types/predicates/predicate_raw_slice/Forc.toml b/packages/fuels/tests/types/predicates/predicate_raw_slice/Forc.toml
index cc6891685..bbc4bece1 100644
--- a/packages/fuels/tests/types/predicates/predicate_raw_slice/Forc.toml
+++ b/packages/fuels/tests/types/predicates/predicate_raw_slice/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "predicate_raw_slice"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/predicate_raw_slice/src/main.sw b/packages/fuels/tests/types/predicates/predicate_raw_slice/src/main.sw
index 3c35e0448..19ba59de2 100644
--- a/packages/fuels/tests/types/predicates/predicate_raw_slice/src/main.sw
+++ b/packages/fuels/tests/types/predicates/predicate_raw_slice/src/main.sw
@@ -13,7 +13,7 @@ struct Wrapper<T> {
 
 fn valid_raw_slice(slice: raw_slice) -> bool {
     let vec: Vec<u64> = Vec::from(slice);
-    vec.len() == 3 && vec.get(0).unwrap() == 40u8 && vec.get(1).unwrap() == 41u8 && vec.get(2).unwrap() == 42u8
+    vec.len() == 3 && vec.get(0).unwrap() == 40 && vec.get(1).unwrap() == 41 && vec.get(2).unwrap() == 42
 }
 
 fn valid_vec(vec: Vec<raw_slice>) -> bool {
diff --git a/packages/fuels/tests/types/predicates/predicate_std_lib_string/Forc.toml b/packages/fuels/tests/types/predicates/predicate_std_lib_string/Forc.toml
index 3572429ca..a0adb8428 100644
--- a/packages/fuels/tests/types/predicates/predicate_std_lib_string/Forc.toml
+++ b/packages/fuels/tests/types/predicates/predicate_std_lib_string/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "predicate_std_lib_string"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/predicate_tuples/Forc.toml b/packages/fuels/tests/types/predicates/predicate_tuples/Forc.toml
index 9ae81c1ae..cb27d8cdb 100644
--- a/packages/fuels/tests/types/predicates/predicate_tuples/Forc.toml
+++ b/packages/fuels/tests/types/predicates/predicate_tuples/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "predicate_tuples"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/predicate_u128/Forc.toml b/packages/fuels/tests/types/predicates/predicate_u128/Forc.toml
index 42300980e..c49f6811f 100644
--- a/packages/fuels/tests/types/predicates/predicate_u128/Forc.toml
+++ b/packages/fuels/tests/types/predicates/predicate_u128/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "predicate_u128"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/predicate_u256/Forc.toml b/packages/fuels/tests/types/predicates/predicate_u256/Forc.toml
index 92e420a9d..83e962967 100644
--- a/packages/fuels/tests/types/predicates/predicate_u256/Forc.toml
+++ b/packages/fuels/tests/types/predicates/predicate_u256/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "predicate_u256"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/predicate_vector/Forc.toml b/packages/fuels/tests/types/predicates/predicate_vector/Forc.toml
index 6972a31e7..b35d18c2b 100644
--- a/packages/fuels/tests/types/predicates/predicate_vector/Forc.toml
+++ b/packages/fuels/tests/types/predicates/predicate_vector/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "predicate_vector"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/predicate_vector/src/main.sw b/packages/fuels/tests/types/predicates/predicate_vector/src/main.sw
index da769b493..d23cd2200 100644
--- a/packages/fuels/tests/types/predicates/predicate_vector/src/main.sw
+++ b/packages/fuels/tests/types/predicates/predicate_vector/src/main.sw
@@ -2,5 +2,5 @@ predicate;
 
 fn main(a: u32, b: u64, c: Vec<u64>) -> bool {
     let number: u64 = c.get(2).unwrap();
-    number == (b + a)
+    number == (b + a.as_u64())
 }
diff --git a/packages/fuels/tests/types/predicates/predicate_vectors/Forc.toml b/packages/fuels/tests/types/predicates/predicate_vectors/Forc.toml
index e540774b1..314bd7747 100644
--- a/packages/fuels/tests/types/predicates/predicate_vectors/Forc.toml
+++ b/packages/fuels/tests/types/predicates/predicate_vectors/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "predicate_vectors"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/structs/Forc.toml b/packages/fuels/tests/types/predicates/structs/Forc.toml
index 39840c670..021641985 100644
--- a/packages/fuels/tests/types/predicates/structs/Forc.toml
+++ b/packages/fuels/tests/types/predicates/structs/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "structs"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/predicates/u64/Forc.toml b/packages/fuels/tests/types/predicates/u64/Forc.toml
index 00b64eac3..fcaed98a3 100644
--- a/packages/fuels/tests/types/predicates/u64/Forc.toml
+++ b/packages/fuels/tests/types/predicates/u64/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "u64"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/scripts/options_results/Forc.toml b/packages/fuels/tests/types/scripts/options_results/Forc.toml
index 1364267d7..bb887bee4 100644
--- a/packages/fuels/tests/types/scripts/options_results/Forc.toml
+++ b/packages/fuels/tests/types/scripts/options_results/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "options_results"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/scripts/script_bytes/Forc.toml b/packages/fuels/tests/types/scripts/script_bytes/Forc.toml
index c76090898..4f170b8bc 100644
--- a/packages/fuels/tests/types/scripts/script_bytes/Forc.toml
+++ b/packages/fuels/tests/types/scripts/script_bytes/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_bytes"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/scripts/script_generics/Forc.toml b/packages/fuels/tests/types/scripts/script_generics/Forc.toml
index 9a0a76425..18eb86f42 100644
--- a/packages/fuels/tests/types/scripts/script_generics/Forc.toml
+++ b/packages/fuels/tests/types/scripts/script_generics/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_generics"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/scripts/script_generics/src/main.sw b/packages/fuels/tests/types/scripts/script_generics/src/main.sw
index e7a0e0c57..621ed1f41 100644
--- a/packages/fuels/tests/types/scripts/script_generics/src/main.sw
+++ b/packages/fuels/tests/types/scripts/script_generics/src/main.sw
@@ -14,11 +14,12 @@ fn main(
     bim: GenericBimbam<u8>,
     bam: GenericSnack<u16, u32>,
 ) -> (GenericSnack<u64, u32>, GenericBimbam<u8>) {
-    let bot = GenericBimbam { val: bam.mars };
     (
         GenericSnack {
-            twix: bot,
-            mars: 2u32 * bim.val,
+            twix: GenericBimbam {
+                val: bam.mars.as_u64(),
+            },
+            mars: 2u32 * bim.val.as_u32(),
         },
         GenericBimbam { val: 255u8 },
     )
diff --git a/packages/fuels/tests/types/scripts/script_raw_slice/Forc.toml b/packages/fuels/tests/types/scripts/script_raw_slice/Forc.toml
index 5de7d6466..981c5d8fd 100644
--- a/packages/fuels/tests/types/scripts/script_raw_slice/Forc.toml
+++ b/packages/fuels/tests/types/scripts/script_raw_slice/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_raw_slice"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/scripts/script_std_lib_string/Forc.toml b/packages/fuels/tests/types/scripts/script_std_lib_string/Forc.toml
index 02cf5a266..b5e72eb3e 100644
--- a/packages/fuels/tests/types/scripts/script_std_lib_string/Forc.toml
+++ b/packages/fuels/tests/types/scripts/script_std_lib_string/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_std_lib_string"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/scripts/script_tuples/Forc.toml b/packages/fuels/tests/types/scripts/script_tuples/Forc.toml
index f10bf2f1b..f1424f806 100644
--- a/packages/fuels/tests/types/scripts/script_tuples/Forc.toml
+++ b/packages/fuels/tests/types/scripts/script_tuples/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_tuples"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/scripts/script_u128/Forc.toml b/packages/fuels/tests/types/scripts/script_u128/Forc.toml
index 4c1c1b3ac..4a8ef1cc5 100644
--- a/packages/fuels/tests/types/scripts/script_u128/Forc.toml
+++ b/packages/fuels/tests/types/scripts/script_u128/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_u128"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/scripts/script_u256/Forc.toml b/packages/fuels/tests/types/scripts/script_u256/Forc.toml
index 0fe896592..78ceb9b7d 100644
--- a/packages/fuels/tests/types/scripts/script_u256/Forc.toml
+++ b/packages/fuels/tests/types/scripts/script_u256/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_u256"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }
diff --git a/packages/fuels/tests/types/scripts/script_vectors/Forc.toml b/packages/fuels/tests/types/scripts/script_vectors/Forc.toml
index 83b90e60d..af00d0095 100644
--- a/packages/fuels/tests/types/scripts/script_vectors/Forc.toml
+++ b/packages/fuels/tests/types/scripts/script_vectors/Forc.toml
@@ -5,3 +5,4 @@ license = "Apache-2.0"
 name = "script_vectors"
 
 [dependencies]
+std = { git = "https://github.com/FuelLabs/sway", branch = "upgrade/fuel-core-v0.20.1" }