Sui’s testnet v1.81.1 release, published on October 6, 2026, rolls out protocol version 138 and a suite of node‑level and API refinements aimed at improving performance, observability, and developer experience.
At the protocol level, the update introduces a new gas model implementation that does not affect user transactions but optimizes fee calculations. A memory invariant check for reference/value usage in PTBs has been added, helping catch potential bugs early. The flag `check_object_funds_withdraw_in_execution` is now enabled on testnet, ensuring that object fund checks run during execution. Transaction effects no longer report dependencies, keeping the effects encoding lightweight while retaining object version and metadata integrity. In the consensus handler, colliding deferred‑transaction keys are merged rather than overwritten, preventing newer deferred transactions from unintentionally displacing earlier ones.
Node‑specific changes give operators more control and visibility. Validators can now pull transactions from a consensus‑side pool at block proposal time, with a configuration toggle to revert to the previous admission‑queue behavior. Fullnodes are no longer restricted to preferred proposers for simulated transactions, and an optional metric `epoch_execution_time_observer_tracked_object_utilization` can be enabled to monitor object usage by name. These adjustments streamline node operation and reduce configuration friction.
API improvements target both gRPC and GraphQL. Rosetta now fetches the latest checkpoint data in a single request, eliminating transient “Checkpoint N not found” errors that occurred when load‑balanced fullnodes were out of sync. GraphQL gains several new fields: `derivedObject` and `multiGetDerivedObjects` on `IAddressable`, `Query.multiGetDynamicFields` for bulk dynamic field retrieval, a nullable `Balance.coinMetadata` field, and a resolved `Transaction.effects.checkpoint` field for subscription deliveries.
For developers, the release offers a cleaner, more predictable execution environment and richer data access. Validators benefit from more flexible transaction handling and enhanced observability. The changes are largely backward‑compatible, requiring no immediate action from users, but they lay groundwork for future protocol evolution.
Overall, Sui’s v1.81.1 update reinforces the network’s focus on stability, observability, and developer ergonomics, positioning the testnet for the next wave of feature rollouts and mainnet readiness.