We had 2 pagemanager panel variants that were broken after the 8.3 update because panels changed the layout names without providing an upgrade path.
I had to change the layout from "onecol" to "layout_onecol" manually in the config file and run "drush cim".

This is not an easy task for beginners :)

Comments

aspilicious created an issue.

nagy.balint’s picture

nagy.balint CreditAttribution: nagy.balint commented

Maybe this is related #2867565: Update page manager to support Drupal 8.3 and Layout Discovery

There is an update hook in page manager which supposed to change that, but for me it does not work.

wesleymusgrove’s picture

wesleymusgrove CreditAttribution: wesleymusgrove commented

I also had this issue with Panels changing it's layout from "onecol" to "layout_onecol". I was trying to update core to 8.3.1, but I was using Bootstrap Layouts 8.x-4.1, which needed to upgrade to 8.x-5.x-dev and use the new Panels 8.4.x in order to lose the dependency on contrib layout_plugin and use the new layout_discovery in core. After making config changes to rename the layout, drush cim didn't recognize any pending config changes to import. I couldn't figure out why that was happening, so I manually changed the config in the database (ugh). Related: #2867535: Bootstrap Layouts 8.x-4.1 incompatible with Drupal 8.3.0