AppStream 0.9 Brings Many Changes, Breaks API/ABI

Version 0.9 of AppStream is now available. As a refresher, AppStream is a FreeDesktop.org specification backed by multiple major Linux distributions as a cross-distribution effort of standardizing Linux component metadata.

The AppStream 0.9 release breaks API/ABI compatibility with older versions of the specification, there is now full integration with the APT package manager, various classes have been modernized, the AppStream CLI has a new install command, and there are several fixes.

AppStream 0.9 changes from its release this weekend can be found via this commit.

Additionally, there is now full DEP-11 support in Debian. DEP-11 is a YAML-based version of the AppStream specification for Debian-based systems. Details on that full DEP-11 Debian support can be found via this blog post.