darktable is probably a good example of a package where even security
support doesn't make much sense.
- The code is changing very quickly to support new camera hardware;
upstream already considers the version in Jessie obsolete.
- It's consumer/desktop code. I guess there's no server infrastructure
depending on photo editing software. I'm just not that sympathetic to
the individual user who hasn't upgraded from squeeze.
- The software is quite demanding; essentially it is barely functional
on 32 bit machines because of memory demands. So I doubt very much
there are many people running it on old computers.
- The development version (for stretch) will actually be more secure,
since it eliminates libraw, a constant source of CVEs.
My expectation when uploading a backport is to support it until the next
stable release. Sorry LTS people, but in this case your itch is not my
itch. If that's wrong, please let me know, and I'll think very carefully
about what I backport in the future.