You have applied the Updates for Skype for Business Server 2015. When you run the Test-CsDatabase cmdlet to test the configuration of the Skype for Business Server databases, you could notice that the installed local XDS (Master) database version isn't matched with the "Expected Version".
This example verifies the databases that are installed on the local computer.
You can see that the versions of InstalledVersion and ExpectedVersion are different. It's expected that the installed version for local XDS version is the same as the expected version after installation.
This issue can be safely ignored as there is no impact to functionality. This issue will be fixed in a future cumulative update.