Hello! The "This application can't run on your PC" issue with Bitrix Desktop on Windows Server 2012 R2 is most likely related to OS incompatibility, as 2012 R2 is already outdated. There are no official archives of older versions of Bitrix Desktop, but you can try searching on unofficial sites (be careful with security) or specialized forums. Bitrix24 documentation usually focuses on server requirements, not on client applications. It is recommended to check error logs, try compatibility mode, upgrade the OS or consider using an older version of Bitrix Desktop if you find one. In the long run, upgrading Windows Server to a newer version will be the best solution.