Base rolled out its Cobalt upgrade for the third mainnet, introducing Validity Transactions that let users submit time-bound transactions that only become eligible if predefined conditions are met, boosting control over when transactions can be included.

The Cobalt hard fork went live on Base’s mainnet on or around September 30, 2026, after a test on Sepolia, with a smooth rollout across the network.

Cobalt advances Base’s tokenized finance push, following the July activation of the B20 standard for stablecoins, tokenized real-world assets, and other fungible tokens.

B20’s transfer rules remain in force for normal transfers, including sender/receiver checks and executor permissions, while seizure rules operate independently.

A deprecated burnBlocked function remains callable to destroy tokens from accounts blocked by transfer policies; seizures do not automatically extinguish balance unless paired with a burn.

Composite Policies let issuers combine allowlists and blocklists with OR/AND logic, enabling reuse of live policies like KYC and sanctions lists without offchain syncing.

Issuers must configure which accounts lose transfer exemptions for seizures; without a SEIZE_EXEMPT_POLICY, those accounts are exempt by default, making explicit eligibility settings essential.

Issuers can appoint authorized administrators to move tokens from holders’ wallets with holder-consent not required, and Base can forbid initiating transfers itself.

The administrative transfer tool, seizeWithMemo, allows on‑chain recording of source, destination, amount, and memo for moves by authorized admins, an issuer-controlled optional capability.

Trades can stay private until they’re included in a block, reducing front-running and information leakage around trigger events.

Cobalt enables scheduling token display multiplier changes for corporate actions like stock splits, without altering on‑chain balances, supported by ERC-8056‑compliant balance representation changes and B20 updates.

ERC-8056-aligned corporate actions support pre‑scheduled balance representation changes, so issuers can reflect events like stock splits without minting or burning tokens, while keeping balances intact.