Blossom, the next major upgrade of Zcash, is scheduled to activate on or around Dec. 11, 2019, at block height 653600.
This mandatory network upgrade is designed to improve scalability and user experience by cutting block times in half (to about 75 seconds), making transaction confirmations faster, doubling network throughput and keeping transaction fees low.
To keep the emission rate and halvening schedule of Zcash unchanged, the halved block times also require that the per-block reward be halved. The emission rate per time, however, remains unchanged.
Other values based on block intervals will also be updated accordingly, such as end-of-service halt, default transaction expiry, and the number of confirmations required to consider a transaction final.
Improved transaction capacity
While Zcash is already one of the most actively used cryptocurrency networks, it has the capacity to handle even more transactions per day. In our conversations with developers who are launching a new app or a business that uses cryptocurrency, we’ve confirmed that scalability is crucial. Many of these inventors and business owners choose which networks to build upon, in part, based on their perception of the future scalability of a network.
The Blossom upgrade immediately demonstrates that the Zcash network can make pragmatic engineering decisions to increase the capacity of the network while maintaining our high standards for security and reliability. It is a prelude to our long-term initiative to drastically improve Zcash scalability.
Network upgrade pipeline
Blossom is the first network upgrade that uses the Network Upgrade Pipeline (NUP) established by the Electric Coin Co. at the end of last year. This pipeline is a process mechanism for safely shipping new protocol upgrades in Zcash. The NUP breaks down the release process into specific periods of focus, including feature selection, auditing, code implementation and partner adoption. For details on adjustments to this process since its initiation, see the follow-up forum posts focusing on clarifying details and enhancing community engagement.
Upgrading and more info
For more information about the Blossom upgrade, see the network upgrade FAQ and the Blossom information portal, and/or join the forum. The network upgrade guidelines list what is necessary (if anything) for third parties to get ready for Blossom.
For technical details on the block target spacing, see the specification in ZIP 208.