Base Activates Denim Upgrade Introducing 200-Millisecond Native Blocks
Base activated the Denim upgrade on November 5, introducing 200-millisecond native blocks and replacing Flashblocks, while addressing subsequent transaction delays and a separate software bug.
The Base network activated the Denim mainnet upgrade on Thursday, November 5, but soon after encountered transaction inclusion delays and an elevated rate of empty blocks. According to the official Base status page, the upgrade went live at 18:00 UTC. An update published at 18:14 UTC indicated that the development team was investigating periodic lags in transaction processing, while deposits, withdrawals, and bridge services remained operational.
Denim introduces native blocks at a 200-millisecond cadence, millisecond-resolution timestamps, and enhancements to network transfers and policies. Prior to the upgrade, users relied on Flashblocks to provide intermediate fast confirmations. Base documentation specifies that Denim replaces Flashblocks, requiring applications to transition to native blocks and standard RPC streams.
The 200-millisecond rate shortens block inclusion times, though it does not guarantee instant finality. Network congestion and communication with Ethereum can still influence completion times. Additionally, Base advised node operators to update to version 1.5.1 prior to activation to ensure compatibility.
Concurrently, Base addressed a separate software bug that could have caused an incorrect state root calculation. The company confirmed that user funds were unaffected, block builders were patched, and operators were urged to upgrade to version 1.5.3 to prevent validator stalls. Base stated there is no verified causal link between the upgrade and the transaction delays.
