How can I roll back ?

There are new image sizes so you need to regenerate your thumbnails. Use this or a similar plugin:

https://www.ads-software.com/plugins/regenerate-thumbnails/

Or you can download the old version here:

https://github.com/edwardr/staffer/releases/tag/1.3.3

This is a great plugin to handle WP.org plugin and theme rollbacks:

WP Rollback

Unfortunately since the old plugin is not in the WP repo, WP Rollback is not an option. I did a manual rollback with a few hiccups that I ironed out. Remember to backup the site prior to doing this.