Blocked/filtered network
Please refer to the wiki Getting Around Blocked or Filtered VoIP Network.
IPv6
Need detailed guide.
Relevant links:
Address resolution: https://github.com/pjsip/pjproject/issues/1926
DNS SRV resolution: https://github.com/pjsip/pjproject/issues/1927
NAT64
QoS
Apple SO_NET_SERVICE_TYPE: https://github.com/pjsip/pjproject/issues/1964
IPV6_TCLASS: https://github.com/pjsip/pjproject/issues/1963
Standalone ICE
TCP
Trickle ICE
IP address change
Please see the wiki Handling IP Address Change. Note that the guide is written using PJSUA API as a reference.