In a supported installed release, Help > Check for Updates checks for a complete update to your edition. Automatic checking is enabled by default; you can turn it off in Help and still check manually. An update is downloaded only after you choose to install it. Choose Remind Later to keep working.
Stable is the default channel. Preview is optional and may be less stable. Switching back to Stable waits for a newer Stable build; it does not downgrade. Help > About shows your installed version and build.
Save and close documents in other tools, stop running games and previews, and close other programs using this installation. The updater asks you to save source changes. Cancel a save or Windows authorization prompt to keep the IDE open. It never forces an editor to close. Each edition uses separate packages and update settings.
Setup copies changed shipped files to the preservation workspace you choose before replacing them. Custom files remain in the installation. Choose a workspace outside the installation; existing preserved copies are never overwritten. Keep projects and custom libraries in your own workspace.
If an installation is interrupted, Blitz3D+ refuses to start a partial toolchain. Close its programs and run the same complete installer again, selecting the same installation directory. Your saved projects are retained. Setup keeps a full repair copy outside the installation and displays its path. You can also use your original authenticated download if the launcher is missing.
Do not delete the installation marker or manually copy DLLs between editions. A full verified repair clears the marker. This update process does not provide automatic rollback.
Development and portable copies do not install updates automatically. Use a complete authenticated installer to migrate, retaining your old folder and custom files until you have checked the new installation. If your release says updates are unavailable, follow its manual download instructions.