Changes to file open behavior in classic Teams will occur from late February to late March 2024. Shared channel files will open in the browser, while OneNote files will temporarily open in the browser. Some Word, Excel, and PowerPoint files pinned as tabs will be read-only. Users should upgrade to new Teams or 1.6.00.34970 and above versions of classic Teams.
Applies to: Microsoft Teams
Source: mc.merill.net — data via Merill Fernando's open archive (MIT).