CANTON 3.4 TO CANTON 3.5 TRANSITION

1. #1Amanda Martin21-04-2026source ↗
   Update: 2026-04-20
   
   See details in the long-term SV Operations schedule
   
   Phase 1: Splice 0.5.x releases pause, and multiple new Splice Daml models go into effect
   
   Splice 0.5.18 is now available on DevNet and TestNet, and rolls out MainNet this week.
   

   • This is final feature release of the Splice 0.5.x release line. If issues are found in this release, a Splice 0.5.19 release will be created that will contain patches only.

   
   
   Daml Models and configuration settings going live on MainNet in Phase 1:
   

   • Development Fund Manager Party is now live on MainNet as of April 15th.
   • April 20th: CIP-0104 Traffic-based App Rewards Increments 2 and 3 arrive on MainNet with Splice 0.5.18
     • Increments 2 and 3 are complete, ahead of schedule, and have been included in Splice 0.5.18. Please see the "Note" section in the Splice 0.5.18 release notes for details.
     • This enables API support for precise traffic costs per transaction (as used for application reward attribution), earlier than the original plan of mid-May.
     • Increment 4 is currently on track to be available on MainNet by the end of June.
   • May 5th: Daml models from Splice 0.5.16 go live on MainNet. All Validators must upgrade to Splice 0.5.16 on MainNet before this date.

   
   
   Phase 2: Splice 0.6.x Release line. Splice 0.6.x begins to introduce features from Canton 3.5 as part of the standard bundle. Protocol-breaking changes remain behind feature flags.
   
   

   • Most important: Splice 0.6.x will introduce Logical Synchronizers, along with the ability to upgrade between two physical synchronizer nodes while preserving the same Logical SynchronizerID
   • This will allow protocol-changing upgrades to take place without pausing Daml transactions. Topology transactions, like adding new nodes, onboarding parties, and vetting Daml models, do pause during protocol-changing upgrades.

   
   
   Major Milestones for Splice 0.6.x:
   

   • April 27th: Splice 0.6.0 goes live on DevNet. Logical Synchronizer introduced.
   • April 30th: Validator Liveness Rewards reduced to zero (0).
   • Late May: Super Validators practice an upgrade using a Logical Synchronizer (aka Logical Synchronizer Upgrade / LSU) on DevNet. No actual protocol changes will be introduced in this practice.

   
   
   Phase 3: Upgrade Global Synchronizer networks to Canton Protocol 35
   

   • After proving out Logical Synchronizer upgrades on Splice 0.6.x, all three Global Synchronizer networks will perform a Logical Synchronizer upgrade to Canton protocol Version 35.
   • Final timing and numbering of this upgrade, and the specific Canton 3.5 features to be included along with it, is still TBD. New features will roll out over time, relying on LSUs to minimize impact on Node Operators and App Providers.

   
   
   Major Milestones for Phase 3:
   

   • Early June: LSU on DevNet introduces protocol upgrade and major new features. TestNet LSU follows one week later.
   • Mid-June: LSU on MainNet introduces protocol upgrade. New features introduced, following the same feature flags and upgrade procedures introduced on DevNet and TestNet.