I agree with Maxim Sobole.
I recently had a project that used Freeswitch and Kamailio.
loadmodule ims_registrar_pcscf .so loadmodule ims_auth.so modparam(ims_auth, "registration_qop”, “auth,auth-int”)
... freeswitch REGISTER qop=auth,auth-int REGSTER qop=auth-int 401 ...
I will modify the FreeSWITCH source code to disable auth-int.