common version number

[kinook]

That depends on what source control system you're using. If you're using SourceSafe, its ss.exe command-line tool (which the VBP SourceSafe action wraps) outputs a report of the differences between the versions specified. In the following step, you would need to parse the output (available in the %LASTSTEP_OUTPUT% macro), probably using a Run Script step, to determine if the output contains changes or not. You would need to compare the output of a no-diff and diff run to determine if there is a reliable comparison that can be made, and then implement logic to perform the comparison.