Unusable post-iOS11 update – Fantastical Calendar Review

I’ve loved this app for the past couple years I’ve had it, but I think I’m done using it. Ever since iOS11 it has become UNusable. It is soooo unresponsive it’s a joke, except that I’m trying to organize my life so it’s not funny. Updates don’t seem to matter. Any help would be great, otherwise, it was a good run.
Review by EffAppleAndU2 on Fantastical Calendar.