Cobalt is additive-only. It does not change or remove any Beryl selector, event topic, or error
selector. Symbols that supersede Beryl symbols are deprecated rather than deleted, so existing
integrations remain callable.
Cobalt has not activated yet. The changes below are not callable until Cobalt activates.
B20 Asset: scheduled multiplier updates
The B20 Asset multiplier surface becomes conformant with ERC-8056
and the B20 Asset multiplier migration details:
Applications should use the ERC-8056 names and move routine multiplier changes to the scheduled
updateUIMultiplier function.
B20 Asset and Stablecoin: seize surface
Cobalt adds seizeWithMemo,
an administrative balance-reassignment operation gated by SEIZE_ROLE.
It also adds a SEIZE
pause vector and two policy slots. burnBlocked
is deprecated in favor of seizeWithMemo, but remains callable and unchanged for compatibility.
Seize is opt-in per token and has no effect until the issuer sets
SEIZE_HOLDER_POLICY.
To destroy supply after a seizure, call burn(uint256) separately.
PolicyRegistry: composite policies
PolicyRegistry adds composite policies that combine two to four existing simple policies using an
OR (UNION) or AND (INTERSECT) gate. See the composite policy details
for the selector mapping and edge cases. Integrators can create and update them with
createCompositePolicy
and updateComposite
instead of duplicating policy logic off-chain.
Existing createPolicy and createPolicyWithAccounts integrations do not otherwise change; they
only gain a new revert path for the previously unreachable composite policyType.
Full Base Standard changelog
For selector-level details, including exact function selectors, event topics, error codes, and
edge-case behavior, see the Base Standard changelog. 
