Base Mainnet Activates Denim Upgrade With 200ms Block Times

The shift from Flashblocks pre-confirmations to native blocks with their own hashes, state roots and receipts is the real substance here: it changes what an onchain confirmation actually means on Base, and matters most to teams that built assumptions around pre-confirmation semantics. The B20 changes around transfer-agent approval and reusable address lists point at tokenized-asset issuers, where compliance controls are the gating concern. The millisecond BaseTime clock alongside second-granularity block.timestamp is worth watching, since the gap between the two could trip up contracts that rely on timing. Whether builders migrate cleanly off pre-confirmations is the open question.