Canton 3.4 to Canton 3.5 Transition

Please review the latest update for the Canton 3.4 to Canton 3.5 transition.

Update date: 2026-06-12
Full details are available in the long-term SV Operations schedule.

Current Status

Phase 1: Complete
Phase 2: Complete

Phase 3: Global Synchronizer Upgrade to Protocol 35

All three Global Synchronizer networks will perform a Logical Synchronizer Upgrade (LSU) to Canton Protocol Version 35.

Minimum Splice version for validators: Splice 0.6.5

DevNet

Status: Complete

TestNet

Topology Freeze: 2026-06-16 at 13:00 UTC
Upgrade: 2026-06-17 at 13:00 UTC

MainNet

Topology Freeze: 2026-06-26 at 13:00 UTC
Upgrade: 2026-06-27 at 13:00 UTC

App Provider Impact During LSUs

During Logical Synchronizer Upgrades:
- Party onboarding, package vetting, and other topology transactions will pause for 24 hours before the LSU
- These actions will resume immediately after the LSU completes
- Daml transactions may be delayed for seconds to minutes at the moment of the LSU
- App providers should experience no other impact

Traffic-Based App Rewards

Traffic-based App Rewards are scheduled as follows:

June 30: Daml models from Splice 0.6.7 become effective. All nodes must upgrade to Splice 0.6.7 before this date.
July 7: Dry run of traffic-based app rewards begins on MainNet
July 28: Traffic-based app rewards go live on MainNet

This is tentatively expected to require upgrading validator nodes to Splice 0.6.9, though the final version number is still to be confirmed.

Phase 4: Retiring CometBFT

The Canton team has prepared a new Canton-native BFT ordering service to replace CometBFT.

Tentative LSU dates to adopt CantonBFT are below. All times are 13:00 UTC, with topology freeze set 24 hours earlier.

DevNet LSU: Wednesday, July 8
TestNet LSU: Wednesday, July 22
MainNet LSU: Saturday, August 8
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