To remove the engineering overhead of supporting two separate UI codebases, Acumatica plans to fully retire its Classic interface with the 2026 R2 update, currently slated for release in the fall of 2026. All users moving to 2026 R2 will run the Modern interface with no fallback option. Versions prior to 2026 R2 keep Classic available under standard lifecycle policy, but Acumatica has stopped functional enhancements to the legacy interface.
This retirement coincides with an even more stringent technical deadline. Effective Nov 17, 2026 Chromium-based browsers like Microsoft Edge and Google Chrome will eliminate XSLT support due to security vulnerabilities. Because Classic UI screens rely on XSLT, they will fail to load in these browsers after this date. In mixed-use environments, only the Classic screens will be affected, while Modern screens will remain fully operational.
The important deadline to watch is Nov 17, 2026, when browsers like Chrome and Edge stop supporting the Classic UI. Acumatica will release a patch for Classic UI users on versions 2025 R1 and newer, but if you are on version 2024 R2 or older, you won’t get it and must upgrade or switch to Firefox to keep working. Consultants should check their clients’ versions and custom setups right now to avoid a sudden shutdown when the browser updates roll out.
If you’re an Acumatica user or partner looking for additional details on the Modern UI, acu-connect is hosting a webinar on May 21 presented by Nicole Ronchetti.
Register for “From Classic to Modern: What’s New in Acumatica’s UI & What to Watch For
Source:
Announcement: Classic UI Deprecation in 2026 R2 and FAQ
Chromium XSLT Deprecation Affecting Classic UI [Action Required]
