WordPress.org

1. Upload custom-field-revisions to the /wp-content/plugins/ directory
2. Activate the plugin through the 'Plugins' menu in WordPress
3. Set up which fields should be handled by the plugin under Settings / Custom Field Revisions

Optional

If you want the "Compare revisions" feature in WordPress to show differences in your custom fields there is a patch included in the assets folder. The plugin will work fine without this hack but for now this is included until I find a way of acheiving the feature. Use at own risk! :)

You need to apply the revision.patch to wp-admin/revision.php and check the box under Advanced section in the plugin settings page to get it working.

IMPORTANT: Do not check the box UNLESS you have applied the patch. It will make the plugin work incorrect.