After receiving the same error after update. I eventually found that the fix for me was to disable gravity forms and gravity plus through myPhp. Once disabled I was allowed back into the back end. Once in, I performed the pending update on the gravity + plugin and then enabled both plugins again and everything seems to have been resolved.
I decided to come back and offer my solution despite the harsh insult of being called impolite and suggesting I was interrupting people in my first ever attempt to become active in the support community.
I hope this helps anyone else with this problem.
I am getting this same error. I hit update on the gravity forms plugin and can’t get into the backend now at all.
