Testnet v1.20.0-rc is live with Protocol v23, new gRPC integrations, and changes across nodes, indexers, and CLI tools. REST API is officially deprecated and will be removed in v1.21. Operators and developers need to adjust configurations and workflows accordingly.

Protocol Updates

• Protocol Version 23: Introduced with this release.
• TxContext Changes:
  • Added sponsor field (#10611).
  • Added reference_gas_price, gas_price, and gas_budget fields (#10729).
  • Made gas_budget public (#10739).

Node Changes

• FastCommitSyncer: Now enabled by default. Disable it by setting enable_fast_commit_syncer: false in the node config (#10902).
• REST API Deprecation: REST API server is deprecated and will be removed in v1.21. Internal consumers now use gRPC instead (#10754). Migrate to gRPC APIs immediately.

Indexer Updates

• gRPC Integration:
  • --remote-store-url and --rpc-client-url now use fullnode gRPC (#10081).
  • Ensure nodes are running v1.19.0+ with enable-grpc-api: true explicitly set, as it’s disabled by default.
  • Deprecated CLI commands will be removed in v1.23.
• iota-data-ingestion-core:
  • Update to the latest version before v1.21 to avoid losing REST API support (#10754).
  • CheckpointReaderV1 will be deprecated in v1.21. Switch to CheckpointReaderV2 via IndexerExecutor::run_with_config (#10963).
  • Custom indexers must use CheckpointReaderV2 to handle hybrid historical storage when fullnode pruning is enabled.
• Migration Required: Update IOTA Indexer instances and restart the writer service to prepare for index removal in v1.21 (#10976).
• Alternative Checkpoint Sources: Sync checkpoints from historical and live storages (#10789).

GraphQL Changes

• gRPC Integration: --node-rpc-url now uses the fullnode’s gRPC API for transaction execution (#10081). Ensure enable-grpc-api: true is set on the fullnode.
• Migration Required: Update GraphQL and restart the service to align with the new indexer migration (#10976).

CLI Updates

• Command Relocations:
  • iota start and iota genesis moved to iota-localnet (#10663).
  • iota genesis-ceremony, iota fire-drill, and iota replay moved to iota-tool (#10663).
• Vec Support: Added in --auth-call-args (#10600).
• Removed Commands: iota client name auction subcommands (bid, claim, metadata, start) removed (#10952).

REST API

Deprecated in this release. Removal scheduled for v1.21. Migrate to gRPC APIs (#10754).

Key Takeaways

• Protocol v23 introduces new fields in TxContext, making gas-related data more accessible.
• gRPC is now the standard for node, indexer, and GraphQL interactions. REST API is on its way out.
• Indexer and custom tooling need updates to support gRPC and prepare for upcoming deprecations.
• FastCommitSyncer is enabled by default for nodes but can be turned off if needed.

Full details and the changelog are available here.

Sources: v1.20.0-rc