The code preparations for the Network Upgrade 5 consensus rules are finished and included in this release. The following ZIPs are being deployed:
- ZIP 216: Require Canonical Jubjub Point Encodings
- ZIP 224: Orchard Shielded Protocol
- ZIP 225: Version 5 Transaction Format
- ZIP 239: Relay of Version 5 Transactions
- ZIP 244: Transaction Identifier Non-Malleability
NU5 will activate on testnet at height 1,590,000, and can also be activated at a specific height in regtest mode by setting the config option
-nuparams=f919a198:HEIGHT.
The testnet activation of NU5, and zcashd v4.5.0 itself, is aimed at enabling existing Zcash users to test their software and make the necessary changes to be compatible with the new consensus rules. In particular:
- Wallets should start adding support for v5 transactions.
- Miners and mining pools should ensure that their software is compatible with the semantic change to the block header specified in ZIP 244
A subsequent v4.5.1 release in the coming weeks will add support for generating and using Unified Addresses (ZIP 316), which will enable zcashd wallets to interact with the Orchard shielded pool.
As with previous network upgrades, it is possible that backwards-incompatible changes might be made to the consensus rules in this testing phase, prior to setting the mainnet activation height. In the event that this happens, testnet will be rolled back in v5.0.0 and a second testnet activation will occur.
See ZIP 252 for additional information about the deployment process for NU5.
Rejecting unknown CInv message types
Previously, if zcashd received an inv or getdata message containing unknown CInv message types, it would ignore them and process the remainder of the message. Starting with v4.5.0, zcashd will instead drop the entire inv or getdata message and reply with a reject message. This will enable node operators to discover whether their nodes are sending unexpected CInv types; in particular, node operators should ensure their software does not produce the MSG_WTX CInv message type intended for the Bitcoin network, which is incompatible with the MSG_WTX CInv message type defined in ZIP 239 (which will be used from NU5 activation for advertising v5 transactions).
Deprecated or removed RPCs
The ‘account’ API inherited from Bitcoin Core has been disabled since the
launch of Zcash. Following its deprecation in Bitcoin Core v0.17 and removal
in Bitcoin Core v0.18, we have now removed the API from zcashd.
