Overview of Teams Desktop Client Auto Update Process

Hello Markus_Johansson Thanks a lot for an interesting question. However seems like MS has never released/published any release notes for Microsoft Teams desktop clients and are being only updated and deployed with a frequency of every 2 weeks and most of the users' desktop clients are being updated as per the auto update process in place. 

First of all as a best practice I would suggest everyone to be always be on the latest available MS Teams Desktop client version for leveraging most of the latest features and at same time for also being secured and compliant. 

However the easiest way to backtrack the installed previous versions of MS Teams on a given desktop/machine can be tracked from SquirrelSetup-Teams.log of MS Teams Diagnostic Logs (Use Alt+Ctrl+Shift +1 for downloading the Ms Teams Diagnostic logs) and the given file can be located under the Desktop folder and might give insights into the versions installed across your machine previously.

Though its not recommended to roll back to a previous version until any serious issues/concerns with latest versions impacting the productivity, the below mentioned download file link did work absolutely fine and downloads the required backtracked version which can be verified by navigating to Properties and Details and check the version details of the given executable as shown in below screenshot.

https://statics.teams.cdn.office.net/production-windows-x64/1.4.00.29473/Teams_windows_x64.exe

As per my previous checks with Public Preview there has been no changes in the Teams desktop client version, rather by  enabling the Teams Public Preview by navigating to Ellipsis and Select About → Public preview. Select Switch to Public preview. would enable preview features which might be still under development and not usually available under Public release. 

Hope this answers and clarifies your queries.