This is work in progress, but I just wanted to share the news: I have Kolab 16 packages for Fedora 25 (with PHP7), built on copr!
The support for Fedora 24 is broken in OBS, ticket: https://git.kolab.org/T1564. Fedora 25 was added after that, but it is broken as well, see for example https://obs.kolabsys.com/package/show/Kolab:Winterfell/libcalendaring
I was looking for alternatives to OBS. Today I can announce that the combination of Copr & LBS works! See also http://www.pokorra.de/2016/12/lightbuildserver-0-5-with-support-to-build-on-copr/
I still have some issues with building erlang packages, because they depend on specific versions, and the packages in Kolab 16 are older than in Fedora 25. Therefore I have disabled guam in the current packages. For details: somehow I cannot build erlang-eimap because it does not recognise erlang-lager. If I install an older version of erlang-rebar, then that works! But guam also requires erlang-test_server and erlang-webtool, which are not included by erlang 19.x packages in Fedora 25 anymore. I can build the older version of erlang from OBS, but then erlang-eimap needs to use the older version of erlang as well… So there is still some work to do…
The next step will be to merge my changes to the packages (maintained in https://github.com/tbits/lbs-kolab/tree/Kolab_16TestFedora25) into Kolab Winterfell on OBS, and perhaps even into Kolab 16 on OBS.
My nightly Kolab tests ran successfully on Fedora 25, see https://lbs.solidcharity.com/package/tbits.net/kolab-test/kolab-test#Kolab16_fedora/25/amd64
To test Kolab 16 on Fedora 25, use this button to create an instance for free for 2 hours on Dply.co!