Base's Cobalt Upgrade Adds Conditional Transactions and Token Seizure

Base activated its Cobalt upgrade on mainnet on 30 September, the third hard fork the Coinbase-built layer-2 network has run in 2026. Two things shipped with it. The first is a transaction format that lets a signed transaction sit dormant until a condition written on chain is satisfied, so an order can wait for a price or a block without being sent again. The second is a set of three changes to B20, the token standard behind Coinbase's tokenized stocks, among them a function that lets an authorised administrator reassign a holder's balance. Node operators had to update first. Every account read here calls the activation uneventful.

What a dormant transaction does

Base calls the new format a validity transaction. A user signs it once and attaches the conditions under which it may be included; it stays private and unexecuted until those conditions hold. The worked example The Block gives is a swap that becomes eligible only if a pool's price reaches a stated level in USDC before a given block. Nothing is resubmitted while it waits. That is the part that matters for anyone re-sending the same order every few seconds.

"The API is neutral infrastructure that provides advanced traders with the added benefit of keeping their submissions private until they land," Base said.

The Crypto Times carries a different sentence as Base's own words on the same point: that the interface decides only whether a submitted transaction is eligible for inclusion, and does not pick the trade or set its terms for the user. The two renderings make the same argument in different words, and neither outlet quotes the other.

Live where, exactly

Two accounts published hours apart disagree about where the feature can be used. The Defiant, writing at 19:00 UTC on Wednesday, says Base's documentation lists validity transactions on Vibenet and Base Sepolia, both test networks. ETH Daily, the same day, says they are live on mainnet. Neither account mentions the other, and they do not reconcile. Base's own upgrade page did not resolve at the address tried for this piece.

Three changes to the standard behind the stock tokens

B20 is the format Coinbase's tokenized equities use, and the Cobalt changes are built for issuers of those. They are:

Composite policies combine allowlists and blocklists with AND/OR logic, so an issuer can require a know-your-customer allowlist and a blocklist of restricted addresses at once, reusing live policies without keeping an off-chain copy in step.
Scheduled multiplier updates align the B20 multiplier with ERC-8056, letting an issuer book in advance how balances will display after a corporate action such as a stock split. The display changes; the underlying balance does not.
seizeWithMemo applies where seizure is switched on for an asset. An authorised administrator can move a holder's balance as a transfer, writing source, destination, amount and a memo on chain.

The demand those answer is visible elsewhere. Aave V4 began taking Coinbase stock tokens as collateral on Base this year, and US regulators handed tokenized venues a five-year exemption from exchange registration. No issuer has said publicly that seizure is enabled on a live asset.

What has not been counted

Operators had a version to run. Crypto Briefing puts the requirement at Base v1.4.2 or newer and the activation at 18:00 UTC; The Crypto Times describes an 18:00 to 20:00 UTC window for the same event. The fork spent a week on Sepolia first and existing transaction formats keep working, so applications needed no changes. Binance paused Base transfers around the switch. Crypto Briefing alone reports two further items in the fork, a framework for scheduling future upgrades with less downtime and TEE signer registration moved fully on chain, and it alone names a next fork, Denim, for October.

Base has said where it wants to go next: block times cut from two seconds to 200 milliseconds, native smart accounts with sponsored gas, and support for selected Glamsterdam improvements. No dates are attached. What nobody has published is usage. There is no count of validity transactions submitted since Wednesday evening, and until there is one, the case for the format rests on the example in the announcement.