Release Notes: v4.3.0

                  .   ★   .                                       .   ★   .

                                                          ♛
                                                          │
                                                          │
                                                          │
                                                          │
                                                          │
                                                          │
                                                          │
                                                          │
                                                          ♟


                       v 4 · 3 · 0  —  promoted at the eighth rank.
                                thanks for the long game.

                  .                                                       .

Date: 2026-05-20
Tag: v4.3.0
Base: v4.2.1
Range since rc.1: v4.3.0-rc.1..v4.3.0 — four follow-up fixes

Summary

v4.3.0 promotes v4.3.0-rc.1 to stable after one rc cycle. The release is dominated by PXE / wallet-side improvements, a new opt-in SQLite kv-store backend, and Aztec.nr / TXE ergonomics. See the v4.3.0-rc.1 release notes for the full breaking-change list and detailed highlights, and CHANGELOG.md for the complete categorized commit list.

Only four small fixes landed between rc.1 and stable — all around macOS install ergonomics and release-image metadata.

What contract developers should care about

• Two breaking changes carried over from rc.1:
  • aztec init / aztec new now scaffold a counter template — any tooling or docs relying on the prior default contents must update (#22751).
  • aztec-nr's history module now consumes shared protocol-circuit utilities — direct consumers of internal history-module helpers must adapt.
  • Migration steps live under ## 4.3.0-rc.1 in docs/docs-developers/docs/resources/migration_notes.md.
• Aztec.nr / TXE ergonomics:
  • Initial handshake registry contract with non-interactive handshake function (#22854).
  • call_self stubs for utility functions (#22885).
  • Contract function return types and parameters are now asserted serializable at compile time (#22877).
  • TXE gains oracle versioning and basic gas settings, mirroring production behavior more closely (#23285, #23289).
• Cross-contract utility calls: end-to-end support for nested utility calls in PXE and TXE, with authorization hooks (#23007, #23064, #22822).
• CLI: 2-crate scaffolds, contract version stamping in artifacts, aztec profile gates --json, aztec-nr-dependency version assertion (#21007, #22550, #22860, #21245).

What node operators should care about

This release is wallet/dev-side-heavy. Notable for ops:

• Sequencer signs the last block before archiver sync (#22117) — correctness/ordering improvement around block signing.
• Release image now stamps stdlib/package.json with the release version (#23393) — fixes a published-artifact metadata mismatch that affected downstream consumers of the stdlib package.
• Several smaller aztec-up install-path fixes; if you bootstrap nodes via aztec-up, macOS install ergonomics are improved (see "What changed since rc.1" below).

What wallet / PXE users should care about

• New opt-in SQLite kv-store backend (#22658, #22759, #23089, #23231): SQLite-on-WASM-over-OPFS implementation of the PXE / wallet kv-store, alongside existing LMDB and IndexedDB backends. A page-level-encrypted variant is available for stricter browser environments. Opt-in at wallet construction time; existing stores continue to work unchanged.
• Materially faster PXE sync — batched nullifier sync across scopes, batched log RPC calls, prefetched class-id hints, short-circuited block-header lookups at the anchor block, parallel per-scope contract syncs (#23129, #23131, #23123, #23130, #23100, #23088, #22525).
• PXE correctness fixes worth knowing:
  • Dropped tagging indices no longer crash PXE on sync (#23044).
  • Anchor-header threading in PXE simulation paths (backport of #22679).
  • Origin/contract address mismatch now throws instead of silently producing wrong simulation results (#22637).
  • Race conditions in block-stream event handling serialized away (#22635).
  • setSenderForTags scope correctness restricted to the current call (F-564, #22672).
• wallet-sdk heartbeat for liveness signalling (#22948).

What changed since v4.3.0-rc.1

Four follow-up fixes — all small:

• add_crate.sh portability on macOS (#23335): use perl -i instead of GNU-specific sed -i.
• aztec-up macOS install (#23310): fall back to no-timeout when /usr/bin/timeout is absent.
• Release image metadata (#23393): stamp stdlib/package.json with the release version.
• CI (#23318): reduce backwards-compat e2e timeout.

Reference

• v4.3.0-rc.1 release notes — full breaking-change list, detailed highlights, notable bug fixes
• CHANGELOG.md — complete categorized commit list
• Migration notes — under ## 4.3.0-rc.1