I'm struggling to solve one problem with 503 reply code.

Kamailio receives 503 and changes it to 500, with error in log

WARNING: script writer didn't release transaction

I inspected incoming 503 (from Cisco gateway), everything seems to be ok except for Via:

SIP/2.0/UDP localip:5060;branch=z9hG4bK47e3.c400aa13.0,SIP/2.0/UDP ip2:5060;branch=z9hG4bK37170104;rport=5060

Does kamailio support this kind of Via?

Thanks,

Mino