How to tell which version of a application is running

[Ralf Mardorf]

On Wed, 19 Apr 2017 10:50:52 +0200, Ralf Mardorf wrote:
>2. This isn't a silver bullet, you can do it again and again. This kind
                                    ^^^
            Oops, this should read "can _not_"
>of backporting might not work for another version of "tracker" again.