Minecraft Launcher

You should ALWAYS make backups before updating.

As with any other piece of software, updates may go wrong for many reasons, including but not limited to: the launcher, the hardware, your custom configuration, the mods you added... and, rarely, FO as well.

Installer

Follow the installation instructions again.

You may find a paigaldaja_meta.json file in the same folder as the installer. Don't worry: this is just a configuration file for smoother future updates.

Manual

If you've installed FO manually, you must reinstall it for every update.

Follow the installation instructions again. You may skip step 1 because Java is already installed.