Comment # 2 on bug 1227361 from Mara Raram

(In reply to hui from comment #1)
> Your repolist seems to be a bloody mess. You are mixing perl packages from
> different devel repos which can‘t work.You need to find out from where you
> installed perl-GSSAPI-0.28-1.153.x86_64 as it is neither in any official
> openSUSE Tumbleweed repo. Also this package has completely different version
> numbers in the perl devel repo.

Thanks for that. zypper se -vx listed it as "system package".
I forced the instatalation of version perl-GSSAPI-0.28-1.155.x86_64 
and a subsequent zypper dup went through without problems.