I think I understand the issue: previously rtpengine module will pass-thru the command
DTLS=off.
In 5.1.2 we have, diff from 5.1.1 to 5.1.2:
+ else if (str_eq(&key, "DTLS"))
+ ng_flags->transport |= 0x104;
now 5.1.2 no longer pass-thru DTLS=off, so rtpengine has different behaviour.
DTLS=off is treated as UDP/TLS/RTP/SAVP.
This could be considered a regression as rtpengine uses the DTLS key for its own
purposes.
Thanks
Anthony