libbellesip1 4.4.21+dfsg-1 (amd64 binary) in ubuntu hirsute

 Belle-Sip is a new SIP stack (RFC3261) developed by the Linphone team.
 .
 Belle-Sip supports multiple transports at the same time, has a dual
 IPv6 and IPv4 stack, is fully asynchronous and implements the
 +sip.instance and alias parameters. It also handles network
 disconnections better, offers a privacy API and supports rich presence.
 .
 SIP/TLS is handled by mbed TLS (by way of bctoolbox), not OpenSSL.