What's new in Plone 6 Classic UI

• HTML markup is now based on Twitter Bootstrap 5.

• Twitter Bootstrap 5 icons are now included.

• Bootstrap JavaScript is available by default.

• JavaScript has been modernized.

• RequireJS has been removed.

• Module Federation support for add-ons.

• jQuery has been updated.

• The TTW theming editor has been removed. Through-the-web theming is limited to downloading and uploading themes.