New Features:

• Introduce the Notification v2 portal. This updated version of the Notification portal supports a plethora of new fields for notifications, such as sounds, categories, purpose, and more.
• Introduce the USB portal. This portal allows apps with relevant permissions to enumerate and acquire access to specific USB devices.
• Introduce a new SchemeSupported method to the OpenURI portal. This new method allows apps to know ahead of time if the host system is able to deal with a particular scheme.

Enhancements:

• Continued the move towards Python-based tests. This should simplify the test setup in the project quite significantly, and also will allow removing the cyclic dependency between libportal and XDG Desktop Portal.
• Introduce umockdev-based tests.
• Improve the icon validator so it can deal with memfd-based icons.
• Clarify behavior of the Settings portal for non-standardized keys.
• In the Global Shortcuts portal, clarify that the result the BindShortcuts
• of may be a subset of all requested shortcuts.
• Add a documentation page about icon validation requirements.

Bug Fixes:

• Fix memory leaks in the Background, Email, and Global Shortcuts portals.
• Fix a general file descriptor & memory leak.
• Fix a regression in the Settings portal.
• New and updated translations.