An change was mad upstream to disallow use of RC4 by default (an additional configuration parameter has to be set to allow it):
https://github.com/krb5/krb5/commit/1b57a4d134bbd0e7c52d5885a92eccc815726463

This restriction is also part of MS-KILE:
https://learn.microsoft.com/en-us/openspecs/windows_protocols/ms-kile/6cfc7b50-11ed-4b4d-846d-6f08f0812919

This change was reverted to avoid conflicts with the crypto-policy system. But it may still be needed for restricting use of RC4 for session keys specifically.