Hello, I see you removed also the flag T_ASYNC_CONTINUE that marked the transaction being in a t_continue operation -- some of the changed chunks (there are few more related): - if ( t->uac[b].last_received<200 && !((t->flags&T_ASYNC_CONTINUE) && b==t->async_backup.blind_uac)) + if (t->uac[b].last_received<200) Was that needed and is the new code (all those conditions) now safe? Overall the flag was not related to async_mutex and can be kept even when using the reply_lock. In my code with defines the flag was left in place, protected by reply_lock. Cheers, Daniel On 13/05/15 09:15, jaybeepee wrote: -- Daniel-Constantin Mierla http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda Kamailio World Conference, May 27-29, 2015 Berlin, Germany - http://www.kamailioworld.com