I have an old version of Glyphs that I’m not quite sure how to remove. Any suggestions? There is only one Glyphs application in the application folder.
You could just delete the old version. Open a file and then right click the old app in the Dock and from the Options menu, choose ‘Show in Finder’.
Select any .glyphs file in Finder, press cmd+i. In the panel, find the ‘Open with’ section. Select the version you like to be used from the popup and then press the ‘Change All …’ button.