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ZEC $1,408 Base Cobalt Upgrade Lets Token Issuers Move Seized Balances Not Burn Them
The layer-2 network's latest mainnet update replaces a balance removal tool that destroyed tokens with one that transfers them to a chosen address.
Key takeaways
- Cobalt launched Sept. 30. Base's Cobalt mainnet upgrade went live on September 30, 2026, following scheduled maintenance.
- New seizure replaces burn. The seizeWithMemo function replaces the deprecated burnBlocked tool that destroyed seized tokens.
- Combined lists cut upkeep. Issuers can merge two to four allowlists or blocklists with AND/OR logic to reduce manual work.
What happened
Coinbase's Base layer-2 network activated its third network upgrade, called Cobalt, on mainnet on September 30, 2026. The update introduces new functionality for issuers of B20, Base's native ERC-20-compatible token standard. The core new tool is seizeWithMemo, which allows authorized administrators to move a holder's seized token balance to a specified address, such as a recovery wallet, with an onchain record, instead of destroying the tokens entirely. This replaces the burnBlocked function from Base's prior Beryl upgrade, which could only burn the tokens of blocked holders, burnBlocked has been deprecated but remains callable.
Why it matters
The shift gives token issuers greater flexibility for handling restricted balances, as seized tokens remain in circulation rather than being removed from the total supply. The upgrade also adds two additional features: the ability to combine two to four existing allowlists or blocklists, including those maintained by third parties like KYC providers, using AND or OR logic, removing the need for issuers to maintain their own offchain combined lists that could become outdated, and Validity Transactions, which let traders submit transactions with attached conditions that must be met before the transaction is included in a block, with the conditions kept private until execution.
Background
Base first launched its B20 token standard in July 2026 as part of its Beryl upgrade, which introduced initial freeze and blocklist powers for token issuers. Cobalt is the network's third overall upgrade, with planned future updates including Base Transactions for smart-contract wallets, native support for fee payments on those wallets by third parties, and reduced block times from two seconds to 200 milliseconds.
Questions readers ask
What is Base's Cobalt upgrade?
Base's Cobalt upgrade is the layer-2 network's third mainnet update, launched on September 30, 2026. It adds new tools for B20 token issuers, including a balance seizure function that transfers rather than burns tokens, combined allowlist/blocklist rules, and Validity Transactions with private pre-execution conditions.
What does the seizeWithMemo function do?
seizeWithMemo is a new B20 token function introduced in the Cobalt upgrade. It lets authorized token issuers move a holder's seized balance to a specified address, such as a recovery wallet, with an onchain memo, instead of destroying the tokens. The function is opt-in per token, and issuers control who can use it.
What are Validity Transactions on Base?
Validity Transactions, added in the Cobalt upgrade, let traders submit transactions with attached conditions that must be met before the transaction is included in a block.
