I had to pin the inflxudb docker image used for testing to version 1.8.4 because the new version 2.0 breaks the tests:
#273

However, this is not great: we want to test with the latest influxdb version and therefore it would be great to upgrade our code so that the test environment is compatible with the last influxdb version. It should be just a matter of setting the authentication credentials correctly.

I think we have to write a new timeseries backend for Influxdb > 2.0 and keep the current backend for Influxdb <= 1.8.