Hi,

I'm the author of cryfs, a cryptographic file system. In the Ubuntu repositories, there's currently cryfs 0.9.9 in bionic and cryfs 0.9.7 in artful. I think it would make sense to also push 0.9.9 to artful. Changes between the versions are minor.


Reasoning:
Cryfs 0.9.6 and 0.9.9+ produce compatible file systems, while opening a file system with 0.9.7 or 0.9.8 will destroy compatibility with 0.9.6 (0.9.6 will refuse to open it afterwards). After that, compatibility with 0.9.6 can be re-established by opening the file system with 0.9.9, so it's reversible, but it still means you can't use these versions on the same file system. Versions 0.9.6 and 0.9.9+ can be used on the same file system without issues. I recommend not using 0.9.7 or 0.9.8 anymore.

Detailed technical description (feel free to skip):
The reason is that when 0.9.7 loads an older file system (say 0.9.6), it asks users to "migrate" the file system to 0.9.7, even though there have been no storage format changes between the versions. Then, the file system will be marked as a "0.9.7" file system. Loading it in 0.9.6 will fail in the future because of this marking, even though it's still the same storage format. Some users have an old 0.9.6 Debian version and asked for compatibility. For this reason, version 0.9.9 re-established this compatibility by marking its file systems as "0.9.6". This means that cryfs versions 0.9.6 and 0.9.9 can be used alongside each other and run on the same file system. Also any future file systems, until there is a breaking change in the storage format. However, once opened with 0.9.7 or 0.9.8, the file system marking will change and 0.9.6 will refuse to open it until it was opened with 0.9.9, which sets the marking back to 0.9.6.


Regards
Sebastian Messmer


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