> ## 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.

# 3.5.2

> Canton 3.5.2 release notes.

# Release of Canton 3.5.2

Canton 3.5.2 has been released on June 03, 2026.

## Summary

This is a maintenance release that fixes an out of memory issue during synchronizer reconnect, addresses security vulnerabilities in the Canton docker base image, as well as minor improvements.

## Minor Improvements

* Updated the Docker base image to 1.0.8 to address vulnerabilities in Busybox: CVE-2025-46394, CVE-2025-60876.
* Fix sequencer subscription closing errors `Timeout 9 seconds expired, but readers are still active in Task closing flushing direct-sequencer-subscription`.
* Handle decoding of `ContractId Void` in PQS
* Improve caching of contract key lookups

## Deprecations

### Removal of synchronous processing on the mediator

The synchronous processing mode on the mediator has been removed in favor of the asynchronous one
that offers better performance.

Config path `myMediator.config.asynchronous-processing` has been deprecated as it is on by default now.

## Bugfixes

### (26-002, Medium): OOM from high memory usage after disconnecting and reconnecting from/to a synchronizer

#### Issue Description

Because of the periodic time proof retrieval task (with interval minObservationDuration), the ConnectedSynchronizer
instance cannot be garbage collected right away after a disconnect/reconnect from the synchronizer.

This leads to higher memory consumption which can lead to OOMs.

#### Affected Deployments

Participant nodes

#### Affected Versions

All versions before 3.5.2

#### Impact

High memory consumption and potentially OOM of the participant

#### Symptom

The heap dump shows instances of the ConnectedSynchronizer from previously disconnected synchronizers.
The stack of calls refers to PeriodicAcknowledgements, TimeProofRequestsSubmitterImpl, SynchronizerTimeTracker and finally Clock

#### Workaround

Restart the participant.

#### Likeliness

Sometimes

#### Recommendation

Upgrade to 3.5.2

## 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) |