- Changed configuration options - -includeconf= can be used to include additional configuration files.
- GUI changes - Block storage can be limited under Preferences.
- External wallet files - The -wallet= option now accepts full paths.
- Newly created wallet format - If -wallet= is specified with a path that does not exist, it will now create a wallet directory at the specified location.
- Dynamic loading and creation of wallets - Previously, wallets could only be loaded or created at startup, by specifying -wallet parameters on the command line or in the bitcoin.conf file. It is now possible to load, create and unload wallets dynamically at runtime.
- Partial spend avoidance - A new -avoidpartialspends flag has been added (default=false). If enabled, the wallet will always spend existing UTXO to the same address together even if it results in higher fees.
- 'label' and 'account' APIs for wallet - A new 'label' API has been introduced for the wallet. This is intended as a replacement for the deprecated 'account' API.
- BIP 174 Partially Signed Bitcoin Transactions support - BIP 174 PSBT is an interchange format for Bitcoin transactions that are not fully signed yet, together with relevant metadata to help entities work towards signing it. It is intended to simplify workflows where multiple parties need to cooperate to produce a transaction. Examples include hardware wallets, multisig setups, and CoinJoin transactions.
- Upgrading non-HD wallets to HD wallets - Since Bitcoin Core 0.13.0, creating new BIP 32 Hierarchical Deterministic wallets has been supported by Bitcoin Core but old non-HD wallets could not be upgraded to HD. Now non-HD wallets can be upgraded to HD using the -upgradewallet command line option.
- HD Master key rotation - A new RPC, sethdseed, has been introduced which allows users to set a new HD seed or set their own HD seed. This allows for a new HD seed to be used. A new backup must be made when a new HD seed is set.
- Transaction index changes - The transaction index is now built separately from the main node procedure, meaning the -txindex flag can be toggled without a full reindex.
- Miner block size removed - The -blockmaxsize option for miners to limit their blocks' sizes was deprecated in V0.16.0, and has now been removed.
For full release notes please see the original Bitcoin 0.17.0 document on which the Guncoin 1.6.0 release was based.