There s no need to install/reinstall the new and/or old blendigo. They can run side-by-side. Just needs a little work
Blender stores it's scripts in
.blender/scripts. Once you have installed the "old" blendigo 2.2.1, just go to that directory and rename
blendigo.py into say
bendigo_2_2_1.py.
Open the script. The second line starting with
Name: indicates what will show up in the scripts menu in Blender. So for example put something like
Name: 'Blendigo 2.2.1 old GUI' and save the script.
Then install the new Blendigo.
Exit Blender, restart and Bingo there you have two different Blendigo entries in your scripts menu in Blender. Works for me at least.