> ## Documentation Index
> Fetch the complete documentation index at: https://docs.canton.network/llms.txt
> Use this file to discover all available pages before exploring further.

# 3.5.5

> Canton 3.5.5 release notes.

# Release of Canton 3.5.5

Canton 3.5.5 has been released on June 17, 2026.

## Summary

This is a maintenance release that fixes an exceptional but severe bug around logical synchronizer upgrades and brings a few improvements.

## What’s New

### Dependencies of vetted packages can be unvetted (PV35+)

On synchronizers running protocol versions 35 and above, vetting state change operations on the API (e.g. via `/package-vetting/update`)
allow dependencies of vetted packages to be unvetted safely, without requiring the use of a force flag.
This is consistent with the transaction protocol, which does not require the dependencies of a Daml transaction node package to be vetted in PV35+.
**Note**: For protocol versions 34 and below, the package dependency vetting restrictions remain unchanged.

### Minor Improvements

* Updated docker base image from 1.0.8 to 1.0.9, which bumps grpc-health-probe to v0.4.52.
* Reduce memory footprint with streaming of large gRPC responses by avoiding buffering the whole response.
* Improve log message in the sequencer in case queuing the event signal is not possible due to a closed subscription and not describe that case as an error.
* New participant config `canton.participants.myParticipant.parameters.connect-to-synchronizers-on-startup` allows to disable automatic connect to synchronizers
  on startup.

## Bugfixes

### (26-003, High): Restarting stuck sequencer yields to sequencer fork

#### Issue Description

Around LSU: if a sequencer not processing blocks is restarted after upgrade time and before it had the chance to process any block,
it will delete traffic data entries as part of crash recovery.

#### Affected Deployments

Sequencer nodes

#### Affected Versions

All versions before 3.5.5

#### Impact

Sequencer fork

#### Symptom

Inability for participants to connect (cannot get consensus on traffic) or participant disconnecting with SEQUENCER\_FORK\_DETECTED

#### Workaround

Restore from backup

#### Likeliness

Exceptional

#### Recommendation

Upgrade to 3.5.5

## Compatibility

The following Canton protocol versions are supported:

| Dependency               | Version |
| ------------------------ | ------- |
| Canton protocol versions | 34, 35  |

Canton has been tested against the following versions of its dependencies:

| Dependency   | Version                                                                                                                                                                                                   |
| ------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Java Runtime | OpenJDK 64-Bit Server VM (build 21.0.12+2-nixos, mixed mode, sharing)                                                                                                                                     |
| Postgres     | Recommended: PostgreSQL 17.10 (Debian 17.10-1.pgdg13+1) – Also tested: PostgreSQL 14.23 (Debian 14.23-1.pgdg13+1), PostgreSQL 15.18 (Debian 15.18-1.pgdg13+1), PostgreSQL 16.14 (Debian 16.14-1.pgdg13+1) |