Okay, since I still haven't finished posting my 3 posts, and I can't post a link yet.
I will still give some information that will be interesting for people who have already owned an ultro key.
1°) make a backup of the preference folder for people who still have the ultro mode active.
( C:\Program Files\Besti Launcher\SaveData\Preferences )
2°) Launch the game, without launcher if you are afraid of losing the ultro mode.
But how do you keep ultro mode after updating the keys?
3°) Used a standard key, download the latest version, then restore the preferences thanks to the backup you made in step 1. Then launch the game without the launcher, to prevent it from removing the mode Ultro of preferences.
To make it even shorter.
1°) Saved preferences when ultro is active.
2°) Used a basic key then installed the latest version
3°) Restored Ultro preferences then played without the launcher.
There is also another method to download the latest version of the game, without going through the launcher, which allows you to keep Ultro mode.
But I'm thinking of making a video of it someday.