Both in general, and with respect to this plugin.
I've long been using an external InfluxDB and Grafana install with this plugin. I recently started working on an upgrade to the latest-and-greatest versions of things. Grafana v8 was pretty smooth (so far). InfluxDB v2.1, though, is being troublesome. It's.... different, in ways that are very second-system effect.
Most critically, though, the v1 compat layer they have for basic writing, which this plugin uses, isn't quite compatible. The plugin (defensively) always issues CREATE DATABASE when it connects, and the v1-compat layer rejects that, and the query fails. Commenting that out (living dangerously, I suppose) makes it work somewhat (other things, like setting retention, fail but don't block progress), but there are some other issues I haven't run down yet - at least one type mismatch in a string-vs-float context.