Dynamic Upgrades introduces an Ethereum smart contract that stores upgrade timestamps for Base nodes, allowing nodes to query the contract and apply changes live. The EL and CL each run an upgrade-signal poller that reads the contract over L1 RPC, saves the schedule into the client's activation overrides, and applies them wherever the schedule is used. Forks activate at the scheduled time with no restart. We expect the decoupling of node releases and upgrade timestamps to reduce the number of node releases operators need to run. NOTE: This change will be rolled out in metrics-only mode for Cobalt, as we collect data to validate that the upgrades work smoothly.

EIP-8130 will bring Native Account Abstraction to Base and allow us to keep transactions opinionated and optimizable. Compared to the previous generation of Smart Accounts, we’ve been able to dramatically reduce the per transaction cost to end users by over 2x, while not compromising on our scaling goals. Native Account Abstraction makes the following features native to the chain: Batch calls: Group multiple actions into a single transaction Sponsorship: Applications can pay for their users’ gas fees or allow them to pay in any token. Portability: Use the same account on any chain, even those that don’t support Native AA. Quantum Ready: Key rotation and multiple authentication schemes allow users to upgrade to post quantum authentication. High-throughput: Parallel nonces and large sender limits unlock high levels of concurrency. Session keys: Applications can act on your behalf with bounded and revocable permissions or create Sub-accounts: Fully isolated account owned by you and controllable by an application. Metadata: Add memos and attributions to your transactions.

Cobalt will bring the following improvements to the B20 token standard: Pay transaction fees in B20s: as part of our rollout of EIP-8130, users will be able to pay transaction fees in B20s. Schedule Multiplier Updates: allows issuers to schedule (and optionally cancel) a multiplier to tokens. This allows for onchain representation of splits, without needing to mint or burn tokens. Only available on the Asset variant of B20. Transfer blocked: simplifies the current freeze and seize model by reducing the burnBlocked + mint steps into a new transferFromBlocked action. New Policies - Union (||) & Intersect (&&): the Union policy allows asset issuers managing many tokens the ability to share policies by default with the ability to enable overrides per token. The Intersect policy allows asset issuers the ability to compose allowlist behaviors with commonly-needed blocklists.