The version 2.2 is for the AMPPS stack(.i.e. the stack of Apache, MySQL, Php etc and the AMPPS Control Center).
The version 2.5 is for the Softaculous Ampps( i.e. the web interface) that is an addon feature in the AMPPS Stack. It is an auto installer used to install the scripts from its huge library. It is independent of the AMPPS Stack.