Zcash community member ValarDragon has proposed raising the network’s block limit to 8 MB and adding a new shielded pool in NU8, changes intended to expand capacity for shielded transactions.
In a Nov. 9 post on the Zcash Community Forum, ValarDragon put the combined proposal’s potential throughput at about 200 shielded transactions a second. The figure is a projection for the combined proposal, not a measure of current throughput.
The block limit would rise from 2 MB to 8 MB, a fourfold increase. ValarDragon said he might propose a limit above 8 MB, depending on implementation progress at the time of the NU8 poll.
ValarDragon’s proposed NU8 changes also include a transaction format intended to keep hardware wallets that have not been updated from becoming more distinguishable as new shielded pools are added. He proposed post-quantum transparent opcodes using SPHINCs variants at 128-bit and 192-bit security levels.
Another proposal would set a date after which the Sapling pool would stop accepting deposits while continuing to allow transactions and withdrawals. ValarDragon also wants to end consensus branch ID changes at each network upgrade, saying those changes cause wallets to break.
Forum participant str4d said removing branch ID updates would require another way to prevent transactions from being replayed across forks. str4d also called for an assessment of how larger blocks would affect wallets using the current light-client protocol.
Zcash’s previous upgrade, NU7, shortened the target interval between blocks from 75 seconds to 25 seconds. ValarDragon’s proposal addresses a different capacity limit: how much data a block can hold. Its proposed wallet changes also raise questions about compatibility as the network adds shielded pools.
ValarDragon is targeting late January 2027 for NU8. The changes remain proposals and have not been approved.
