Plugins load order

Depending on how the plugin is loaded, it will hook into the WordPress load order at different points (from latest to earliest):

• Manually activated from the wp-admin Plugins screen (supported, but code activation is preferred): before the plugins_loaded hook
• wpcom_vip_load_plugin( 'plugin-name' ) in your theme functions.php (supported, but code activation from client-mu-plugins is preferred): before the after_setup_theme hook
• wpcom_vip_load_plugin( 'plugin-name' ) from client-mu-plugins (recommended): on the muplugins_loaded hook

Sometimes plugins may have dependencies on running before specific hooks, in order to hook on very early actions or filters you will need to load from client-mu-plugins.