Base, the Coinbase-incubated Layer 2, deployed its Denim mainnet upgrade, replacing Flashblocks with full canonical blocks produced every 200 milliseconds, or five per second, according to a statement shared with The Block on Thursday, November 5, 2026.
The report was published on November 6, 2026, at 04:00 UTC+8. Denim is Base’s fourth independent network upgrade, following Azul, Beryl and Cobalt, all implemented in 2026.
Block production and application migration
Under Denim, each block follows its parent exactly 200 milliseconds later. Base said the protocol enforces that interval rather than relying on the sequencer’s clock.
The upgrade retires Flashblocks and changes the behavior of the pending block tag. Applications that relied on Flashblocks must migrate to standard canonical block subscriptions, according to the statement. Base described the changes as making block production “simpler, more consistent, and more reliable”—a characterization from the project.
Millisecond timestamps without changing block.timestamp
Denim introduces BaseTime, giving smart contracts access to Unix timestamps in milliseconds. The Ethereum-compatible block.timestamp retains its whole-second resolution, while new RPC fields supply millisecond timestamps for blocks, transactions and logs.
Base framed more frequent state updates and precise timekeeping as requirements for its focus on trading, financing and payments.
B20 transfer and compliance controls
For tokens using Base’s B20 standard, Denim introduces reusable compliance policies through a NOT operator and extends transfer-executor restrictions to direct transfers. Base also said the upgrade blocks transfers, mints and seizures that would send tokens to the token contract’s own address.
These are changes to token-level controls and execution rules. The supplied announcement does not establish custody arrangements, legal ownership rights or customer protections for products using those tokens.
Base launched in 2023. Its earlier independent upgrades introduced a new client stack and multiproof system through Azul, the B20 token standard through Beryl, and conditional transactions plus expanded B20 compliance features through Cobalt.