Base, Coinbase’s layer-2 network, said its Cobalt upgrade went live on mainnet on Wednesday, adding a new way for issuers of tokens built on B20 to remove a holder’s balance. Instead of destroying the tokens, issuers can now move the balance to another wallet and attach a note that is recorded onchain.
The new function, seizeWithMemo, replaces a tool from Base’s earlier Beryl upgrade. Beryl introduced B20, a token standard native to Base, along with freeze and blocklist powers. Its burnBlocked function could only burn the tokens of a blocked holder. Base said that function has been deprecated, though it remains callable.
Seizure becomes a transfer rather than a burn
Under Cobalt, an administrator authorized by the issuer can send a holder’s balance to another address, including a recovery wallet, in a single transfer. Base’s developer documentation describes the action as “A transfer, not a burn.”
The documentation says seizure is opt-in for each token. The function does nothing until an issuer identifies which holders can be seized and grants seize permission to specific administrators.
Base said in its announcement: “The issuer controls whether seizure is enabled and who is authorized to use it; Base does not initiate or direct this transfer.”
Unchained reported on the launch of B20 in July.
Issuers can combine allowlists and blocklists
Cobalt also lets issuers combine two to four existing allowlists or blocklists into a single rule using AND or OR logic. Those lists can include ones maintained by outside parties, such as a KYC provider. Base’s example requires a holder to appear on a KYC allowlist and not appear on a sanctions blocklist.
The token reads those lists live when checking a transfer, so a change to any one of them applies on the next check.
Before this update, an issuer relying on several lists had to maintain its own combined copy with offchain software. Base said in its changelog that such a copy could fall out of date.
Validity Transactions add conditional execution
Cobalt also introduces Validity Transactions. A trader can sign a transaction and attach conditions such as a minimum account balance, a value stored in a contract, or a block-number deadline. Base waits to include the transaction until every condition is true.
Base’s example is a swap that executes only after a pool’s price clears a threshold.
Base said the feature keeps traders’ submissions private until they land, and its documentation says the conditions themselves are not recorded onchain.
Still, meeting those conditions does not guarantee a place in a block. The documentation states: “Predicates are inclusion conditions. They do not guarantee inclusion or successful execution.”
Third network upgrade, with more changes planned
Base said Cobalt is the network’s third upgrade. Over the coming months, the company said it plans to add Base Transactions, native support for smart-contract wallets, fee payment by another party, and the ability to bundle several actions into one.
Base also said block times are set to fall to 200 milliseconds from two seconds.