Approach

• Review and test integration with upcoming 7.0 WP release. Priority of this ticket is to ensure functionalities remain as they are once WP 7.0 is released
• Review deprecation warnings and fix the ones that can be fixed without large refactoring
• Upgrade WP Core minimum required version to allow using more recent functionalities

Some notable exceptions of issues that couldn't be resolved:

Gallery settings page

The suggested replacement is still marked as experimental. It would be risky to use an experimental component that might change its API within our plugin (our linter advice against it too). Remaining on the deprecated (but still working) component seems safer.

Gallery block

The gallery block styling is enqueued via the enqueue_block_editor_assets hook at the moment. Ideally we should migrate to using a block.json file combined with editorStyle property... however the structural changes are quite large so we might need to have a separate refactor task to upgrade the gallery block to apiVersion 3 with block.json support.

apiVersion 3 means full iframe support within the editor. Unfortunately this doesn't work well with the current structure of this block, as it's currently loading the gallery widget for a live preview within the editor. This is sort of related to the above issue.

QA notes

• Follow any recommended method here to install the latest WP 7.0 RC
• Perform some overall regression testing of the plugin, particularly:
  • the gallery settings page
  • the gallery block on the editor