How to upgrade from Layout Plugin

At this time, Layout plugin and Layout discovery modules cannot be run at the same time in a Drupal 8.3.x instance. (See issue: #2867795: White screen (WSOD @ Drupal 8.3) ERROR: Cannot use object of type as array )

Try the following process to move from Layout plugin to Layout discovery:

1. Remove or at least disable any contrib product that relies on Layout plugin;
2. Disable (maybe even delete) layout plugin
3. Update database schema.

It is best to use the 4.x branch of the following modules when completing this transition:

• Display Suite 8.3.x (beta version available).
• Panels 8.4.x (in development).
• Panelizer 8.4.x (beta version available).

Possible issues:

• #2872957: Document that the 'css' property no longer works after upgrading from layout plugin
• Names changing for bundled layouts, e.g. "onecol" changes to "layout_onecol"; this can be handled via an update script.
• API changes for custom integrations; this needs documentation.

See also:

• See issues: #2811175: [plan] Add layouts to Drupal and #2867795: White screen (WSOD @ Drupal 8.3) ERROR: Cannot use object of type as array
• How to render layouts, the new way.
• Layout plugin documentation