We recommend backing up your data before any type of change. It is not recommended to downgrade your world to an older version as the server can crash.
We always recommend to make a clean install of your server when switching to or from modpacks. Changing your server version from Vanilla to Spigot/Paper, we recommended to keep the same Minecraft version you had before.
Head over to the Game Panel and stop your server.
Navigate to the Versions tab and select the type and version from the list.
Once you've selected the preferred type and version, click on Install to start the installation.
Done! You can now start your server with the new version.
Congratulations, you've successfully changed your server version. If you have any issues or concerns, please contact us through the ticket system.