Comment # 1 on bug 973624 from Wolfgang Bauer

Well, that's not so easy.

okular provides libokularpart, and that had an soname change in 15.12.
On my 13.2 system with KDE:Applications added:
# zypper in okular-15.12.3
Loading repository data...
Reading installed packages...
Resolving package dependencies...

Problem: ruby-kde4-4.14.3-8.2.x86_64 requires libokularcore.so.6()(64bit), but
this requirement cannot be provided
  deleted providers: okular-15.08.3-1.1.x86_64
uninstallable providers: okular-14.12.1-8.1.x86_64[repo-update]
                   okular-14.12.2-12.1.x86_64[repo-update]
                   okular-14.12.3-16.1.x86_64[repo-update]
 Solution 1: Following actions will be done:
  deinstallation of ruby-kde4-4.14.3-8.2.x86_64
  deinstallation of libsmokekde3-4.14.3-8.2.x86_64
  deinstallation of calligra-extras-okular-2.9.11-77.7.x86_64
 Solution 2: do not install okular-15.12.3-3.1.x86_64
 Solution 3: break ruby-kde4-4.14.3-8.2.x86_64 by ignoring some of its
dependencies

Choose from above solutions by number or cancel [1/2/3/c] (c): 

So we'd need to update those as well...