Upgrading from Panels-6.x-3.x to Panels-7.x-3.x

  - Style and layout plugins may no longer be registered by a central hook.
    Only the plugin directories method may be used.

  - Layout 'panels function' is now 'regions function'.

  - Layout 'panels' key is now 'regions'.

  - panels_get_pane_title() deprecated.

  - panels_plugin_get_function() deprecated.

  - panels_required_context removed. These were deprecated long ago and
    existed only to prevent crashes.

  - panels_optional_context removed.

  - $renderer->plugins['layout']['panels'] changed to $renderer->plugin['layout']['regions']

  - display_renderer class is now in 'renderer', not 'handler'.

Upgrading task handlers from Panels 7.x-3.5 or older to Panels 7.x-3.6 and newer:

  - You must specify a storage type for any panels display using your custom task handler.
    For examples, see panels_update_7306.

  - When creating whatever stores the panel, a storage id and storage type must be defined.
    See panels_mini.module for examples inside panels_mini_save and panels_mini_panels_cache_get.

  - A display access plugin must be defined.
    See panels_mini/plugins/panels_storage/panels_mini.inc for an example plugin.