If you are concerned about the security of your SQL Server, you do this.

 SQL Server of different versions are still supported and their version and build number are important for securing your SQL Server.

This KB article (321185) brings together and consolidates all build versions and their current support cycle from SQL Server 2005 through the current version. An EXCEL file that can be downloaded provides the SQL Server's Complete version list.

Go here to get it!

Latest updates and version history for SQL Server - SQL Server | Microsoft Learn

One of the worksheets is shown here for your information from the downloaded EXCEL file.

If you are interested in finding what version of SQL Server you are running, just run the following SELECT query:

SELECT @@Version

You may look at the version when you try to use the Object Explorer in the management studio when you try to connect to a version from the drop-down list.

There are other ways to determine the version of SQL Server Version. This blog has posts on many versions that were used in writing some of my books on SQL Server shown hereunder.

However, for a secured SQL Server you should have the latest update to the version you are running.