I built K master and tried to use 5.2 config. That resulted in error:
Apr 30 15:47:10 salmon /usr/bin/sip-proxy[1659]: ERROR: siptrace [siptrace.c:908]:
w_sip_trace3(): no duplicate_uri modparam nor duplicate uri sip_trace() argument
provided!
I think it has been practice that backwards compatibility is provided by
the next version.