Influxd upgrade not available in 1.8 to migrate to 2.5

__Steps to reproduce:__
List the minimal actions needed to reproduce the behavior.

1. ...
2. ...
3. ...

__Expected behavior:__
Describe what you expected to happen.

__Actual behavior:__
Describe What actually happened.

__Environment info:__

* System info: Run `uname -srm` and copy the output here
* InfluxDB version: Run `influxd version` and copy the output here
* Other relevant environment details: Container runtime, disk info, etc

__Config:__
Copy any non-default config values here or attach the full config as a gist or file.

__Logs:__
Include snippet of errors in log.

__Performance:__
Generate profiles with the following commands for bugs related to performance, locking, out of memory (OOM), etc.

```sh
# Commands should be run when the bug is actively happening.
# Note: This command will run for ~30 seconds.
curl -o profiles.tar.gz "http://localhost:8086/debug/pprof/all?cpu=30s"
iostat -xd 1 30 > iostat.txt
# Attach the `profiles.tar.gz` and `iostat.txt` output files.
```

The report names no files, tests, entry points, reproduction steps, or environment details. Start by obtaining the missing reproduction and version information for upgrading InfluxDB 1.8 to 2.5; done would require a documented and working migration path.

Written by the indexing model from the issue text.