There is an existing 5.0.0 branch where these changes are being made. Once we are a little closer to the release this branch will be merged into master. Anyone is welcome to pick up tasks here and PR into the 5.0.0 branch.

This is a list of proposed breaking changes for the 5.0.0 release. Feedback welcome!

• Remove DrawerHostOpenMode.Model (Added in 4.0.0, Obsolete in 4.1.0)
• Remove MaterialDesignScrollBarThumbVertical and MaterialDesignScrollBarThumbHorizontal replace with MaterialDesignScrollBarThumb
• Consider making recommended theme color classes static.
  • Currently not possible because they implement the ISwatch interface.
• Update ListBoxItem to use theme brush for hover color rather than deriving from the Foreground.
• Update MenuItem to use theme brush for hover color rather than deriving from the Foreground.
• There is a both usage of "Assist" and "Extensions" used. Consider standardizing on naming
• Remove MaterialDesignRaisedAccentButton in favor of MaterialDesignRaisedSecondaryButton
• Remove MaterialDesignFlatAccentButton in favor of MaterialDesignFlatSecondaryButton
• Remove MaterialDesignFlatAccentBgButton in favor of MaterialDesignFlatSecondaryMidBgButton
• Remove MaterialDesignFloatingActionMiniAccentButton in favor of MaterialDesignFloatingActionMiniSecondaryButton
• Remove MaterialDesignFloatingActionAccentButton in favor of MaterialDesignFloatingActionSecondaryButton
• Remove ComboBoxPopupPlacement
• Remove obsolete members from ComboBoxPopup
• Remove obsolete templates PopupContentUpTemplate and PopupContentDownTemplate
• Remove obsolete brushes Theme brush rename #2435
• Replace usages of "Accent" with "Secondary"
• Remove "MaterialDesignNavigatilRailTabControl" it is replaced by "MaterialDesignNavigationRailTabControl"
• Remove RatingBarButton.IsWithinSelectedValue property
• Remove obsolete members from FlyoutAssist
• Remove ShadowDepth
• Remove ShadowAssist.ShadowEdges
• Rename ShadowEdgeConverter to ShadowOpacityMaskConverter to better reflect its usage
• Ensure all styles and brushes that contain the word "Accent" have been replaced with "Secondary"
• Remove PickerInnerPaddingConverter (obsolete in PR Additional SmartHint refactoring #3181)
• Rename all *Mixin classes to be *Extensions
• Remove MaterialDesignTheme.Defaults.xaml in favor of people using either MaterialDesign2.Defaults.xaml or MaterialDesign3.Defaults.xaml
• Ensure all removed obsolete styles exist in the Obsolete shim resource dictionary.
• Remove ITheme in favor of Theme
• Remove IBaseTheme. Its usages are replaced with ThemeExtensions.SetBaseTheme() method.