Erigon v3.7.1 — Velvet Vibrissae

v3.7.1 makes Caplin ready for Glamsterdam on Sepolia. Upgrade Sepolia nodes before 6 October 2026, 13:53:36 UTC (epoch 353024). This bugfix release is recommended for all users; no re-sync is required from 3.7.0. Operators using custom graffiti or non-default Caplin ports should review the breaking changes below.

Breaking Changes

• cl/beacon: prefix custom graffiti with EL+CL client identification by default (#24394) by @lystopad — leaves 19 bytes for custom text, or 25 while the EL version is unavailable; longer text is truncated. Set --beacon.api.preserve-graffiti to keep the full 32 bytes for custom graffiti. Short hex values are right-padded with and without --beacon.api.preserve-graffiti.
• cl/p2p: add QUIC v1 with TCP fallback (#24413) by @domiwei — QUIC defaults to UDP 4001; allow this port through your firewall, or the port configured by --caplin.discovery.quicport (--sentinel.quic.port for standalone Sentinel). Discovery still defaults to UDP 4000. If you use --caplin.discovery.port=4001, set a different QUIC port before upgrading: conflicting discovery and QUIC UDP binds now prevent Caplin from starting. Fixes [#23398].

Bugfixes

• cl, execution: prepare Caplin for Glamsterdam on Sepolia (#24386, [#24399], [#24421], [#24441], [#24458], [#24474], [#24484]) by @domiwei, @yperbasis, @MysticRyuujin, @Bruce039 — aligns Gloas consensus and APIs with consensus-specs v1.7.0-beta.2, corrects Payload Timeliness Committee (PTC) duties and fork-epoch advertising, and preserves slot numbers and block access lists in locally built payloads. Sets the payload deadline to 50% of the slot (6 seconds on Sepolia) and schedules Sepolia's default 200M gas-limit target. Retries retained parent payloads without an EL verdict during sync within the running process.
• execution: release block-builder state after a payload is built (#24478) by @taratorio — cached results kept transaction read sets and contract bytecode alive, causing out-of-memory failures under heavy code-access workloads.
• cl/beacon: publish request blobs on nodes that did not produce the block (#24471) by @lystopad — fixes 500 missing blob bundle when validators publish pre-Gloas blocks to multiple beacon nodes. Fixes [#23112].
• execution/engineapi: wait longer for a busy execution module before dropping a payload build (#24396) by @lystopad — external consensus clients now get up to 6 seconds, or one slot on chains with shorter slots, instead of 500 ms. This avoids missed proposals during background flush and commit. Fixes [#24371].
• db/datadir/reset: reject erigon snapshots reset --local=false when it would mix referenced commitment and state files from different builds (#24401) by @lystopad — checks run before any deletion; --allow-mixed-state overrides the guard.

Security

• cl/beacon, cl/phase1/network/services: prevent unvalidated sync-committee messages from reaching gossip (#24368, [#24384]) by @lystopad — messages outside the allowed slot window are no longer published, cache hits check the block root and signature, and already-published retries are suppressed. Together these changes fix [#24305].

Improvements

• cl/beacon: publish sync-committee messages in the background (#24368) by @lystopad — removes gossip latency from Beacon API responses and reports queue-admission failures to callers.
• cl/antiquary: compress blob snapshot backlogs with multiple workers (#24338) by @lystopad — speeds up archive-node catch-up while keeping one worker at the tip.

Full Changelog: https://github.com/erigontech/erigon/compare/v3.7.0...v3.7.1