Zcashd version lifecycle: the Zcash ecosystem metronome.
Every 16 weeks a Zcashd version dies and a new one is born. This happens whether Zcashd code is being substantially changed or not. Once a version is released, it can’t be stopped. Nobody can tell you which version of Zcashd to run. Zcashd is designed to stop running at a given blockheight and operators have to update their version to keep validating (or mining) blocks. This means that if you need to release a new version of Zcashd, for the case it requires the current supported version to stop working, you need to wait until the End-of-Support (EOS) of the current version.
This means that the feature that you finish developing today in Zcashd, will only see the light of day on mainnet after the EOS date of the current version, when the version that includes that feature becomes the current version (provided that it doesn’t need a transition cycle). Sometimes that could mean a day, others it can mean 16 weeks. That’s how this metronome keeps a decentralized, permissionless and censorship-resistant protocol keeps everyone coordinated in terms of software releases.
The timeline below shows the current Zcash version and the milestones where the support of the next three versions end.
The next Zcashd EOS is January 21st 2026. This entails that whenever the Zcash development teams have consensus that Zcashd deprecation development is complete, then the ecosystem will need a whole EOS cycle to occur in order to deploy the proper versions that will stop the current supported Zcashd version and allow the Zcash maintainers to create and deploy the End-of-Life version of Zcashd.
The Z3 development cross-team group gathered and estimated that it is acceptable to assess that Zcashd deprecation development completion window could span between now and May 2026 (Zcashd 6.10.1 EOS). This leaves the 16 weeks between 6.10.1 and 6.10.2 to be the cycle buffer where the Z3 infrastructure could co-exist in production with Zcashd for the case NU7 is set to activate in September 2026
This means that NU7 could be targeted for activation after September 2026 indicated by Zcashd 6.10.2 EOS Milestone provided that it is feature complete and the NU process can be carried out by then, with the good practices that the Zcash core developers have been doing all of these years.
Towards a friction-less Network Upgrade process
Zcash core developers are researching ways to reduce the impact of Network Upgrades that include transaction changes. This means less hassle for wallet and infrastructure providers and a higher pace for smaller updates even if they do include transaction format changes. Core developers are committed to improve UX for all ecosystem actors including the most tech savvy ones.