How can I safely upgrade Blender while preserving the ability to roll back to the previous version?

The safest way to upgrade Blender while preserving a rollback path is to avoid the installer's default "upgrade" behavior and instead treat each version as a standalone installation. Because Blender is largely portable, you can run multiple versions side-by-side without them interfering with one another.

Recommended Upgrade Workflow

To ensure you can revert to a previous version without losing preferences or add-ons, follow these steps:

1. Back Up User Configuration

Blender stores user preferences, scripts, and add-ons in a version-specific folder. Before upgrading, manually back up the configuration directory to prevent the new version from potentially modifying or migrating your old settings in a way that is irreversible.

• Windows: %AppData%\Blender Foundation\Blender\
• macOS: ~/Library/Application Support/Blender/
• Linux: ~/.config/blender/

Copy the folder corresponding to your current version (e.g., 3.6) to a secure backup location.

2. Install the New Version in a Separate Directory

Do not run an installer that targets the existing Blender installation folder. Instead:

• Portable Method (Recommended): Download the .zip (Windows) or .tar.xz (Linux) archive. Extract it to a new folder (e.g., C:\Blender\Blender_4.0). This keeps the binaries entirely separate from your previous version.
• Installer Method: If using an installer, specify a custom installation path that differs from the current version.

3. Verify and Roll Back

Once the new version is installed, verify the installation by checking Help > About Blender. If you encounter crashes or incompatible add-ons, rolling back is as simple as launching the executable from the previous version's folder.

Technical Considerations

While the binaries are separate, Blender versions typically create their own configuration folders in the paths mentioned above. However, some third-party add-ons may store data in shared global directories. If an add-on fails in the new version, check if it shares a data folder with the old version, as this could lead to configuration corruption.

Verification Checklist

Action	Verification Method
Installation	Confirm two distinct folders exist for the two versions.
Rollback	Launch the old executable to ensure it still opens and loads projects.
Preferences	Check Edit > Preferences in both versions to ensure settings are independent.

Diagnostic Detail: Are you using a system-wide package manager (like apt or pacman) to manage Blender? If so, the recommendation shifts toward using Flatpaks or AppImages to avoid dependency conflicts during a rollback.