Base, the Ethereum Layer 2 incubated by Coinbase (NASDAQ: COIN), has activated Cobalt, its third mainnet upgrade of 2026. The hard fork went live on September 30 after a Sepolia rollout the week before.
The release focuses on two user-facing changes: Validity Transactions, which let traders attach on-chain conditions to signed submissions, and a set of additions to B20, Base’s native token standard for issued assets.
Validity Transactions allow a user to sign a transaction once and submit it with predicates over chain state.
Base withholds the payload until every condition matches.
Typical predicates include a pool price floor, an account balance, a storage slot value, or a block-number deadline.
In one published example, a swap stays ineligible while a pool sits below 4,000 USDC and only becomes eligible if that price is reached before a given block. If the deadline arrives first, the transaction is never included.
Conditions themselves are not written on-chain, so the submission can stay private until it lands.
Meeting the predicates does not guarantee inclusion or successful execution; the transaction still competes on ordinary fee rules once it is eligible.
B20 arrived with the earlier Beryl upgrade as a precompile that extends ERC-20 behavior for tokenized assets.
Cobalt keeps existing selectors and integrations intact and adds three capabilities.
Composite policies let issuers combine live allowlists and blocklists with AND or OR logic.
A fund can require both a KYC list and an accreditation list without copying member records or running off-chain sync.
Each source list is read at transfer time, so a later removal from either list blocks the next transfer automatically.
Scheduled multiplier updates align B20 assets with ERC-8056.
Issuers can queue a display multiplier change for a corporate action such as a split, cancel it before activation, and apply it at a set timestamp.
Raw balances and transfer logic stay the same; only the UI-denominated view changes.
A holder with a raw balance of 100 would still hold 100 units after a 2x multiplier, while wallets that read the multiplier would show 200.
The third addition is seizeWithMemo.
Where an issuer has opted into seizure, an authorized administrator can move a frozen holder’s balance to another address in a single transfer and attach an on-chain memo.
The function replaces the earlier burnBlocked path for cases where moving funds is preferable to destroying them.
Base does not enable seizure itself; that choice, and the list of authorized callers, remains with the issuer.
Cobalt also includes lower-visibility infrastructure work: an L1 registry that can later hold fork timestamps so upgrades need not be compiled into node binaries, and an on-chain path for registering TEE prover signers by verifying Nitro attestations directly.
Those pieces run alongside the user-facing features and set up later forks.
Base has already pointed to shorter 200-millisecond blocks, protocol-level smart accounts with gas sponsorship and batching, and a subset of Ethereum’s Glamsterdam EVM changes as the next items on the roadmap.
The upgrade tightens Base’s pitch as issuance infrastructure for tokenized equities and other regulated assets while giving professional traders a way to express conditional intent without polling or resubmitting. Indexers need the updated B20 ABI. Existing Beryl integrations continue to work.