Base’s Cobalt upgrade adds another rule to affect token balances

Base’s Cobalt upgrade, scheduled for mainnet Sept. 30 at 18:00 UTC, will let issuers of B20 tokens configure balance seizures separately from ordinary transfer restrictions. For a token that enables the feature, a holder could remain free to transfer while still being eligible for administrative reassignment.B20 is Base’s native ERC-20-compatible token standard, offered in Asset and Stablecoin variants. It already gives administrators control over roles and policies governing balance movements, and now it will also govern the administrative powers over those balances.Role assignments identify who can exercise a particular power, while policy settings determine which accounts an operation can affect. Changing a token’s rules and executing a balance operation involve distinct permission checks.Separate seizure permissionsThe new administrative operation, called seizeWithMemo, moves a specified amount from a holder to another address. It preserves total supply and skips ordinary transfer policies and holder allowances.An issuer must configure which accounts lose their exemption before the function can take their tokens. The setting, SEIZE_EXEMPT_POLICY, exempts everyone when left unse...