Alpha 11 seems to be stable, so i updated my first post with the following information:

What works and what not? Comments
For Alpha 11 consider

• For sideloading warehouse app

• To avoid black rectangle just create your own ambience.

Changelog

• Fixes store and sideloading issues introduced with alpha 10

• Default weather app is installable

• Some icons are fixed, number of columns in folders is raised from 3 to 4

• Pre-installed codec support for mp3/mp4

Overall i can recommend to update from alpha 9 to alpha 11.

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Thank you for your detailed browser performance testing, i like it. On XDA you asked for double tap to wake. To avoid hardware buttons you can try the following: I dont have any bad issues using the low power mode / glance screen in connection with a case: As root
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Without being too optimistic: The chances to get OTA updates are getting better:-)

I do backups of ~/.vault and copy / move files to the underlying primary android os to copy those back, for calendar sync etc.
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This is a general issue which should be fixed in upcoming releases: Not all Jolla store apps are available, you will not see new apps coming in and those apps which you installed do not get automatic updates. But if you own a Jolla maybe you can work around this issue, see below;-)
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Though GPS does not work on Alpha 11 yet you can try the HERE / sailfish-maps app with routing and nearby features if you own a Jolla - dont ask for it. Always as root