Influxdb v2.4 to 2.5 Upgrade, now fresh setup

A few days ago i updated my v1.8 instance to v2.4 (via apt packages)
The Data Upgrade was a trouble for me (running systemd Service)
I realized the upgrade command writes the Data to the current user und copied the data into /var/lib/influxdb (.influxdbv2 folder) and copied the new influxdb config to /etc/influxdb and changed the paths to /var/lib
It was running fine then.

Now an apt upgrade has started ibfluxdb like a fresh install.
Please tell me how to use the v2.5 with the old 2.4 Data?
Running with systemd service

Commandline: apt upgrade
Upgrade: influxdb2-cli:amd64 (2.4.0, 2.5.0), influxdb2:amd64 (2.4.0-1, 2.5.1-1)

problem solved

somehow the /etc/default/influxdb changed or replaced the used config file to config.toml in /etc/influxdb instead influxdb.conf

Hello @iamhermes,
Thank you for sharing your solution!