See https://fedoraproject.org/wiki/Changes/php80 Related to swig bug #1934995
*** Bug 1936325 has been marked as a duplicate of this bug. ***
I will wait until swig is built for PHP 8, and then rebuild libkolabxml.
Support for PHP 8 was added in swig-4.0.2-5.fc35.
Thanks for fixing swig! The libkolabxml Package has now been built successfully for rawhide: libkolabxml-1.2.0-3.fc35