Base, an Ethereum Layer 2 (L2) blockchain incubated by Coinbase, has activated its Cobalt upgrade on mainnet, adding a transaction mechanism that lets users specify conditions for when a transaction can be included, alongside new functions for its B20 token standard.
The upgrade, Base’s third network upgrade of 2026 announced in an X post on Wednesday, introduces Validity Transactions and three B20 enhancements: Composite Policies, Schedule Multiplier Updates, and seizeWithMemo. The changes are aimed at trading workflows and the issuance and administration of tokenized assets on the network.
The Cobalt upgrade went live after a scheduled mainnet upgrade on September 30. Base’s status page listed the maintenance window from 18:00 to 20:00 UTC.
Conditional transactions target trading workflows
The main trading-related change is Validity Transactions, which allow a signed transaction to remain pending until specified on-chain conditions are satisfied.
Under the system, users can submit a transaction through base_sendRawTransactionValidity with conditions tied to factors such as on-chain state or block numbers. Base’s sequencer evaluates those conditions before inclusion rather than requiring users to repeatedly submit transactions.
For example, a trader could specify that a swap should only be included if a particular price threshold is reached and before a specified block number. If the conditions are not met within the defined window, the transaction is not included.
The conditions are selected and signed by the user. Base says the API provides infrastructure for determining whether a submitted transaction is eligible for inclusion rather than selecting the trade or setting its terms on the user’s behalf.
The feature is designed to give traders more control over when and under what conditions transactions enter the chain, while allowing submissions to remain pending until their criteria are met.
B20 changes expand tokenized asset controls
Cobalt also changes Base’s B20 token standard, which is used for assets issued on the network. The upgrade introduces three additions that address transfer restrictions, corporate actions, and administrative transfers.
Composite Policies
Composite Policies allow issuers to combine existing allowlists and blocklists using AND or OR logic. This can allow, for example, a token to require both a KYC policy and an accreditation policy before a transfer is permitted. The individual policy lists remain managed by their respective providers rather than being merged into a separate list.
The change is particularly relevant for tokenized assets that need to apply multiple eligibility or compliance conditions to transfers.
Scheduled Multiplier changes
Schedule Multiplier Updates allow issuers to schedule changes to an asset’s multiplier in advance, including for corporate actions such as stock splits.
The change affects how an asset is represented at the user-interface level rather than changing the underlying raw token balance or transfer mechanics.
For example, a 2x multiplier could cause a wallet or application to display 100 raw units as 200 shares after the scheduled change, without minting or burning tokens.
Base says the functionality aligns the B20 Asset multiplier with the ERC-8056 standard.
seizeWithMemo adds transfer records
Cobalt also adds seizeWithMemo, which allows an authorized administrator of a token with seizure enabled to reassign a holder’s balance as a transfer accompanied by an on-chain memo.
The record identifies the source and destination, the amount transferred, and the memo attached to the transaction. The function is controlled by the token issuer: the issuer determines whether seizure is enabled and which administrators can use it. Base does not initiate these transfers.
From Azul to Cobalt
Cobalt is Base’s third network upgrade of 2026, following Azul in May and Beryl in June. Azul was Base’s first independent upgrade after separating its upgrade cycle from the Optimism Superchain framework, while Beryl introduced the B20 token standard for issuing stablecoins and other assets at the protocol level.
B20 was designed to remain compatible with ERC-20 tokens while adding features for asset issuers, including lower-cost transfers and support for stablecoin-specific use cases. Cobalt builds on that infrastructure with new controls for transfer policies, corporate-action adjustments, and authorized balance reassignment.
Base has also previously shortened the canonical Ethereum withdrawal period from seven days to five and introduced infrastructure changes aimed at reducing node resource requirements.
Implications for tokenized equities
The B20 changes come as Base expands infrastructure for tokenized stocks and other real-world assets. Base has already introduced Coinbase-issued tokenized stocks on the network under the B20 standard. The assets represent shares held with a regulated custodian and can be used across supported onchain applications.
The Cobalt changes address several operational issues that arise when traditional assets are represented as tokens, including eligibility restrictions, corporate actions, and controlled asset recovery. The changes do not themselves create new tokenized securities or determine which assets can be issued. Those decisions remain with individual issuers and applicable market infrastructure.
What changes for network participants
The upgrade also creates technical requirements for developers.
- Advanced traders can use validity transactions to specify conditions governing transaction inclusion.
- Token issuers can use the new B20 functionality for policy combinations, scheduled multiplier changes, and authorized seizure records.
- Indexers need to update to the new B20 ABI associated with the hard fork, according to Base.
Base has also directed issuers to its updated B20 guidance for common token-issuance and asset-management workflows.
Further Base upgrades planned
Cobalt is part of a broader 2026 effort by Base to add infrastructure for trading, tokenization and payments. Base has said future upgrades will include 200-millisecond blocks, down from the current two-second block interval, as well as Base Transactions, which would bring smart-account functionality such as gas sponsorship and transaction batching closer to the protocol level.
For now, Cobalt’s changes are live on mainnet, with validity-based transaction inclusion and the three B20 enhancements available to supported users and applications.
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