You can upgrade Kaspersky Security for Microsoft Exchange Servers 9.5.1 to the current version 9.0 Maintenance Release 6. Upgrading from earlier versions is not supported.
Before updating the application, install the Visual C++ Redistributable for Visual Studio package. The latest versions of libraries of both bitness must be installed by the following links: https://aka.ms/vs/17/release/vc_redist.x64.exe, https://aka.ms/vs/17/release/vc_redist.x86.exe.
The application is upgraded using the Setup Wizard or the command line.
For the correct application operation after updating, update the Anti-Virus and Anti-Spam databases.