As I seem to have looked for this a bunch of times online and still don’t find the right place for it I’ll leave it written here.

  1. Get the new version from here
  2. Go to MAMP in finder
  3. Bin
  4. Rename PhpMyAdmin to PhpMyAdmin-old
  5. Move new PhpMyAdmin in to place and remove trailing details

Done, easy.

I don’t use MAMP Pro so I’m not sure about that