FreeCAD does not start anymore due to missing libboost_program_options

The package for 13.1 requires boost 1.53, not 1.49:

# zypper info --requires FreeCAD
...
libboost_program_options.so.1.53.0()(64bit)
...

Probably you have the Packman repo for 12.3 or earlier?
Please post your repo list:

zypper lr -d