Hello, i will soon move my server on another host, which means on another IP, and i was wondering if i can update the server's IP, or should i add the server again?

You have a few options:

1. Just re-add it
2. Set up a DNS on the old server page, and change the IP the DNS points to when you have the new IP. Note it must use the same ports before and after for this to work.
3. From the old server page, use the Migrate stats function to move the player stats to the new page.