[users] Difficulty installing legacy version

I use an old Mac running OSX 10.11 El Capitan, so I need to use the legacy version of Chirp. Chirp v0.1 is in the Applications folder. Python 2.7 and 3 are installed. "System Preferences > Security > Allow apps downloaded from" is set to Anywhere.

When trying to open Chirp the icon animates slightly as if it is opening, but the animation is shorter than when opening other apps and nothing happens. It looks to me like it begins to initiate and then automatically quits. I get no errors, just a single bounce of the icon and then nothing. Is my computer too old or can I still get it to run?

Many thanks.