Comment 4 for bug 1539430

Also Scope API is included in unity8 package. If unity8 APIs or any Qt/Quick/Web or binding APIs got updated, the framework number should be bumped, which ensure that app or scope works in that rootfs.

There are several API support[1] got dropped or new feature like preview widget and share-data been introduced[2]. The user can have a newer app or scope running in old rootfs, and caused some compatible issue.

I think the best inforamtion for developers are a mapping table of

- ubuntu version from $(system-image-cli -i)
- tag name from $(system-image-cli -i)
- related packages version,
libqt*
qtdeclarative5-*
ubuntu-system-settings
ubuntu-ui-toolkit-theme
unity8-common
unity-webapps-qml
and so on ...

[1] Bug #1542375 “Get rid of the formFactor context property” : Bugs : webbrowser-app package : Ubuntu - https://bugs.launchpad.net/bugs/1542375
[2] Preview widget types | Ubuntu developer portal - https://developer.ubuntu.com/api/scopes/cpp/sdk-15.04.1/previewwidgets/