Greetings,
Is it a warning or an actual error?
Well, it doesn't halt on the sudo apt-get install koha-common, so I am assuming warning. I didn't go further than that.
I'm not all that willing to maintain an alternate version in the repos unless super critical.
I was not suggesting an alternate, suggesting a forced version 4.5.7 which is stable in both Debian and I suspect Ubuntu. That would be a pain, and the goal isn't pain. One goal is easy to maintain.
This said, docbook I think is just a build dependency, not needed at runtime. One of these days I need to separate these out.
If it is just a build dependency, then the message is most definitely a warning and can be ignored. That was something I was wondering as well (is it a just a build dependency?). GPML, Mark Tompsett