Application.BugVersion
From Xojo Documentation
Read-Only Property (As Integer )
The Bug version of the Application. This can only be set in the IDE, but you can read the value in your code.
Notes
Typically version numbers are written as 1.2.3.4 (MajorVersion.MinorVersion.BugVersion.NonReleaseVersion).
Sample Code
Puts all the individual versions together to create the full version: