The interface for settings editors have seen a major overhaul and the advanced settings interface has the following user facing changes:

• A choice of using the old or the new settings widget, which is remembered
• A "hidden" setting allows to bypass the warning before showing the settings tree
• Settings have dedicated editors (spin box, checkbox, colorbutton, etc.)
• The modification of settings is now only executed when apply is pressed
• Current settings are displayed in italic, whereas settings to which changes will be applied are displayed in red

In addition, the settings API has undergone significant changes including:

• Removal of the QgsSettingsEntryByValue class, using the by reference only
• The old QgsSettingsTreeWidget has been renamed to QgsSettingsTreeWidgetOld (in app)

New API classes introduced include:

• QgsSettingsTreeWidget and QgsSettingsTreeModel: tree widget + model to show and edit the settings
• QgsSettingsEditorWidgetWrapper (pure virtual): a base wrapper class to create and handle a setting editor widget
• QgsSettingsEditorWidgetWrapperTemplate (pure virtual): the base class for the wrapper of settings declared in C++ API (using typed methods)
• Classes for settings editors: QgsSettingsStringEditorWidgetWrapper, etc.
• QgsSettingsEditorWidgetRegistry: a registry of the setting editor wrappers