diff --git a/rs/tests/src/orchestrator/upgrade_downgrade.rs b/rs/tests/src/orchestrator/upgrade_downgrade.rs
index 81c262aeb6e..5e89c38d0d5 100644
--- a/rs/tests/src/orchestrator/upgrade_downgrade.rs
+++ b/rs/tests/src/orchestrator/upgrade_downgrade.rs
@@ -1,11 +1,11 @@
 /* tag::catalog[]
-Title:: Upgradability to/from oldest prod replica version.
+Title:: Upgradability from/to the mainnet replica version.
 
 Goal:: Ensure the upgradability of the branch version against the oldest used replica version
 
 Runbook::
-. Setup an IC with 4-nodes NNS and 4-nodes app subnet using the code from the branch.
-. Downgrade each type of subnet to the mainnet version and back.
+. Setup an IC with 4-nodes NNS and 4-nodes app subnet using the mainnet replica version.
+. Upgrade each type of subnet to the branch version, and downgrade again.
 . During both upgrades simulate a disconnected node and make sure it catches up.
 
 Success:: Upgrades work into both directions for all subnet types.
@@ -52,6 +52,7 @@ pub const UP_DOWNGRADE_PER_TEST_TIMEOUT: Duration = Duration::from_secs(15 * 60)
 
 pub fn config(env: TestEnv) {
     InternetComputer::new()
+        .with_mainnet_config()
         .add_subnet(
             Subnet::new(SubnetType::System)
                 .add_nodes(SUBNET_SIZE)
@@ -68,17 +69,17 @@ pub fn config(env: TestEnv) {
     install_nns_and_check_progress(env.topology_snapshot());
 }
 
-// Tests a downgrade of the nns subnet to the mainnet version and an upgrade back to the branch version
+// Tests an upgrade of the NNS subnet to the branch version and a downgrade back to the mainnet version
 pub fn upgrade_downgrade_nns_subnet(env: TestEnv) {
     upgrade_downgrade(env, SubnetType::System);
 }
 
-// Tests a downgrade of the app subnet to the mainnet version and an upgrade back to the branch version
+// Tests an upgrade of the app subnet to the branch version and a downgrade back to the mainnet version
 pub fn upgrade_downgrade_app_subnet(env: TestEnv) {
     upgrade_downgrade(env, SubnetType::Application);
 }
 
-// Downgrades a subnet to $TARGET_VERSION and back to branch version
+// Upgrades to the branch version, and back to mainnet NNS version.
 fn upgrade_downgrade(env: TestEnv, subnet_type: SubnetType) {
     let logger = env.logger();
 
@@ -123,23 +124,10 @@ fn upgrade_downgrade(env: TestEnv, subnet_type: SubnetType) {
     let key = enable_ecdsa_signing_on_subnet(&nns_node, &nns_canister, subnet_id, &logger);
     run_ecdsa_signature_test(&nns_canister, &logger, key);
 
-    let original_branch_version = get_assigned_replica_version(&nns_node).unwrap();
-    // We have to upgrade to `<VERSION>-test` because the original version is stored without the
-    // download URL in the registry.
+    let original_branch_version = "0000000000000000000000000000000000000000".to_string();
     let branch_version = format!("{}-test", original_branch_version);
 
-    // Check that the two versions do not initially match, which could hide failures.
-    assert!(mainnet_version != original_branch_version);
-
-    // Bless both replica versions
-    block_on(bless_public_replica_version(
-        &nns_node,
-        &mainnet_version,
-        UpdateImageType::Image,
-        UpdateImageType::Image,
-        &logger,
-    ));
-
+    // Bless branch version (mainnet is already blessed)
     let sha256 = env.get_ic_os_update_img_test_sha256().unwrap();
     let upgrade_url = env.get_ic_os_update_img_test_url().unwrap();
     block_on(bless_replica_version(
@@ -152,23 +140,23 @@ fn upgrade_downgrade(env: TestEnv, subnet_type: SubnetType) {
     ));
     info!(&logger, "Blessed all versions");
 
-    downgrade_upgrade_roundtrip(
+    upgrade_downgrade_roundtrip(
         env,
         &nns_node,
-        &mainnet_version,
         &branch_version,
+        &mainnet_version,
         subnet_type,
         &nns_canister,
         key,
     );
 }
 
-// Downgrades and upgrades a subnet with one faulty node.
-fn downgrade_upgrade_roundtrip(
+// Upgrades and downgrades a subnet with one faulty node.
+fn upgrade_downgrade_roundtrip(
     env: TestEnv,
     nns_node: &IcNodeSnapshot,
-    target_version: &str,
-    branch_version: &str,
+    upgrade_version: &str,
+    downgrade_version: &str,
     subnet_type: SubnetType,
     nns_canister: &MessageCanister,
     key: VerifyingKey,
@@ -225,15 +213,15 @@ fn downgrade_upgrade_roundtrip(
 
     stop_node(&logger, &faulty_node);
 
-    info!(logger, "Upgrade to version {}", target_version);
-    upgrade_to(nns_node, subnet_id, &subnet_node, target_version, &logger);
+    info!(logger, "Upgrade to version {}", upgrade_version);
+    upgrade_to(nns_node, subnet_id, &subnet_node, upgrade_version, &logger);
 
     // Killing redundant nodes should not prevent the `faulty_node` downgrading to mainnet version and catching up after restarting.
     for redundant_node in &redundant_nodes {
         stop_node(&logger, redundant_node);
     }
     start_node(&logger, &faulty_node);
-    assert_assigned_replica_version(&faulty_node, target_version, env.logger());
+    assert_assigned_replica_version(&faulty_node, upgrade_version, env.logger());
 
     assert!(can_read_msg(
         &logger,
@@ -265,8 +253,14 @@ fn downgrade_upgrade_roundtrip(
 
     stop_node(&logger, &faulty_node);
 
-    info!(logger, "Downgrade to version {}", branch_version);
-    upgrade_to(nns_node, subnet_id, &subnet_node, branch_version, &logger);
+    info!(logger, "Downgrade to version {}", downgrade_version);
+    upgrade_to(
+        nns_node,
+        subnet_id,
+        &subnet_node,
+        downgrade_version,
+        &logger,
+    );
 
     let msg_3 = "hello world after upgrade!";
     let can_id_3 = store_message(
@@ -279,7 +273,7 @@ fn downgrade_upgrade_roundtrip(
         stop_node(&logger, redundant_node);
     }
     start_node(&logger, &faulty_node);
-    assert_assigned_replica_version(&faulty_node, branch_version, env.logger());
+    assert_assigned_replica_version(&faulty_node, downgrade_version, env.logger());
 
     for (can_id, msg) in &[(can_id, msg), (can_id_2, msg_2), (can_id_3, msg_3)] {
         assert!(can_read_msg_with_retries(