Currently the only App for influx that I know of shows at 1.x. I have no experience with it.
If you want a different version, you need another App or someone to update that one.
If you are using Container install, maybe someone has a docker that has a newer version and you could possibly use that.
I had a discussion with Cole (an InfluxDB developer). At the moment, there is no official migration tool available for upgrading from v1/v2 to v3. He did mention that “it’s in the works,” but that was all he could officially share.
Aside from that, I wouldn’t invest time in upgrading to v2. Your current version, 1.8, is stable, fast, and still supported.
Once an official upgrade path becomes available, I assume one of the Home Assistant developers will inform you about the upgrade requirements and tools.
In my opinion, it’s disappointing that there is still no official upgrade tool for an already released version.
1.8 is good and reliable. You also don’t care about potential security issues, it’s a local install.
But I moved to 2.0 quite some time ago (I forgot how I did it) and I can tell you that
just setup a backward-compatible connection in Influx and you can use HA just as before
Influx 2.x offers Flux as language query. If you want to extract and process data from Influx, Flux is amazing. I could do processing on historical data (energy prices, consumption, …) which Influx 1.8 AND influx 3.x do NOT allow unless you write a separate python script. In other words, without any extra software Grafana can plot advanced data analysis.
So do not go to 3.0, your options are stay on 1.8 if you don’t really need any change, or go to 2.x.