Base Launches Denim Upgrade on Mainnet, Swapping Flashblocks for 200ms Block Speeds

Denim phases out Flashblocks, integrates millisecond-accuracy timestamps, and refreshes B20 transfer and regulatory controls.

The fourth mainnet release for Base, called Denim, is now active, with the Coinbase-backed Layer 2 network currently generating a complete canonical block every 200 milliseconds, translating to five blocks per second, as noted in an announcement provided to The Block on Thursday.

Furthermore, the patch brings millisecond-accurate timestamps for smart contracts, together with upgraded transfer safeguards and compliance mechanisms for assets utilizing the B20 standard on Base.

Base explained that the rollout phases out Flashblocks and alters the behavior of the pending block tag, rendering block generation “more straightforward, uniform, and dependable.” Every block is now generated precisely 200 milliseconds after its predecessor, with the network guaranteeing the interval instead of depending on the sequencer clock.

DApps that previously depended on Flashblocks are required to transition to conventional canonical block feeds, the announcement noted.

“Base’s core mission is to onboard the globe to the blockchain, beginning with trading, financial services, and payments,” the announcement stated. “Such applications demand a network that refreshes state frequently and permits developers to calculate time accurately.”

BaseTime and B20 tokens

As outlined in the announcement, the network update also rolls out BaseTime, granting smart contracts access to Unix timestamps measured in milliseconds. The Ethereum-compatible block.timestamp stays unaltered at standard whole-second granularity, whereas fresh RPC endpoints supply millisecond timestamps for blocks, transactions, and logs.

Denim additionally delivers modular compliance rules via a NOT function and broadens transfer-executor limitations to cover direct transfers. In addition, it restricts transfers, minting operations, and confiscations that route tokens toward the token contract’s own address, according to Base.

This enhancement comes after Azul, Beryl, and Cobalt, which were Base’s initial three separate upgrades following its 2023 launch. Azul brought a fresh client architecture and a multi-proof framework, whereas Beryl established the B20 token framework. Cobalt introduced conditional transactions and widened B20 compliance capabilities.