This is an important announcement presenting a change to affect all users of the ‘SysIDE Editor’ extension for VS Code. Here we present the transition to affect all users in the coming days in order to bring SysML v2.0 support, 50x speed-up, and resolution to the reported issues. This transition enables Syside Editor to stay the most accessible (being free), popular, and trustworthy SysML v2 textual editing tool in the new growth & mass adoption stage for the SysML v2 ecosystem (given the SysML v2.0 specification has just been officially released by the OMG).

What is changing

The SysIDE Editor extension (VS Code Marketplace id: sensmetry.sysml-2ls)  available since January 2023 will be deprecated getting the name ‘SysIDE Editor Legacy’ and replaced by a new extension named ‘Syside Editor’ (VS Code Marketplace id: sensmetry.syside-editor) for the current users to install and transition to. The new ‘Syside Editor’, besides providing the same functionality as ‘SysIDE Editor Legacy’ will bring SysML v2.0 specification support, massive 50x speed-up, absence of the known issues affecting the predecessor, while still staying free to use as before just under a different license. The main points of the transition in more detail below.

Current Extension ‘SysIDE Editor’ (VS Code Marketplace id: sensmetry.sysml-2ls):

• receives a final 0.9.1 update that renames it to ‘SysIDE Editor Legacy’ and sets the extension to deprecated status
• continues to work but will no longer be maintained or receive updates
• has its GitHub and GitLab repositories archived and set to read-only

New Extension ‘Syside Editor’ (VS Code Marketplace id: sensmetry.syside-editor):

• released under the ‘Syside Editor’ name
• provides the same functionality as the predecessor
• brings up-to-date SysML v2.0 specification support, 50x speed-up, absence of the known issues affecting the predecessor
• licensed under a new license without source code access 
• remains free to use, non-commercially and commercially

Why the change

The to be deprecated SysIDE Editor Legacy released in January 2023 was built on a different technology stack than our industry-leading Syside Professional Tool Suite, launched commercially in July 2025 and tested by hundreds of users during the Early Adopter Program since September 2024. Syside Pro Suite technology actively developed over the past 3 years beats ‘SysIDE Editor Legacy’ overwhelmingly in all areas, in particular, bringing 50x faster performance. In such this situation, maintaining two totally different implementations with one being so much inferior has become irrational and impractical, especially, given our objective to keep apace with the SysML v2 specification updates and to deliver timely bug fixes to our user community. Hence the decision has been made to have Syside Editor reborn taking advantage of the technological advancements in the Pro Suite for the benefit of all. 

What this means to you

The Benefits:

• Faster updates: Unified development means quicker adoption of SysML v2 changes
• Improved reliability: Bug fixes will be delivered much more rapidly
• Superior performance: The new Syside Editor delivers 50x faster performance
• Consistent experience: reusing technology for Syside Editor from Syside Pro Suite brings same production-grade quality as well as consistency between the tools.  

The Trade-offs:

• Syside Editor will not be supported on the web-based VS Code through vscode.dev . Though we consider bringing such functionality in the future given user interest.
• Source code will no longer be publicly available and a new licence will apply

Timeline

The transition will be completed within two weeks. During this transition period the new Syside Editor will become available on the VS Code marketplace, and the legacy extension will receive its final 0.9.1 update with a deprecation notice as well as links to upgrade to the new Syside Editor extension. We will provide clear migration guidance to ensure a smooth transition for the users.

Closing words 

It has been an exciting growth, learning, and maturation journey with Syside Editor and its incredible global user community to date. However, it is just been the beginning and we are even more excited about entering a new accelerated growth and mass adoption stage for SysML v2 – with a much more powerful & quality Syside Editor available to all, for free. 

Lastly, we are looking forward to seeing all the amazing SysML v2 creations from the global & fast-growing user community. We hope you share your creations using Sysand (more info on sysand.org ), the brand new open-source package manager for the SysML v2 ecosystem developed and brought to you by Sensmetry (the same team & company as behind Syside).

Yours,
The Sensmetry Team

---

Questions? Engage in a Syside community discussion on forum.sensmetry.com or reach out to us at syside@sensmetry.com