Up to 4.16.4 the plugin worked great then when they released 5.0 it didn't play nice with the other plugins (specifically CleanTalk). 1. v5 specifically using the Cloud now to connect means that their IPs are not static and that also means using with another plugin like CleanTalk firewall doesn't work at all for caching. It's pretty much useless. 2. Ironically 4.16.4 worked fine... with CleanTalk's firewall so as of this review I had informed the Founder. He's a bit of a know-it-all type who is very condescending in approach to support. Quite simply if you invest in a tool like FlyingPress you would at some point need to rely on their customer service, it's slow, too basic, asking users to clear cache, somewhat condescending and fails to really provide the necessary solution for the issue at hand.