Historically we use Skype for internal messages at chez moi. The rate of undelivered messages is MUCH higher than it used to be, so we are looking for a replacement. Skype was bought by MSFT a long time ago; and they only care about the Skype business accounts (which from a business perspective makes sense). I have read that MSFT will close its Skype servers at some point (from general news site, not a official MSFT plan, so I'm not bothering with a reference), as they would prefer people to use MSFT teams.
Assumed previous reading, is an architecture level view of SIP + VOIP, P2P networking, encryption architectures.

Software selection metrics

  • Run on ubuntu, android, and supports win32
  • Support some type of messaging
  • Support SIP/VOIP
  • Doesn't eat all battery power, especially when not in active use

Nice to haves

  • Prefer P2P architecture, but that is not compulsory
  • Message edit capacity


Not a candidate, but here is a huge list of VOIP software at 1.

  • Blink project 2 under GNU GPL3 licence. The 3 project has support for SIP, VOIP, IM, MSRP, VNC and XCAP. It claims to have OTR and ZRTP security protocols. The more commercial side is called blink voice 4 5. QT version supports linux, win32; and macs with the older py3/cocoa build. Improved install instructions are at the end on this page; standard install instructions are 6. Doesn't mention message editing at 7
  • linphone project 8 available under GNU GPLv3, git. The wiki 9 says it supports SIP, SIMPLE, RTP/RTCP, and security wise SRTP ZRTP. The wiki doesn't mention messaging, but 10 does. There is a summary architecture diagram at 11. Install instructions for ubuntu are 12 13
  • empathy 14 licence GNU GPL, started life as a chat client but also now supports VOIP. As what was previously a core piece of Ubuntu software, Empathy is very easy to install (package name is empathy). Pls note empathy project owners say that encryption is outside of scope for them. Secondly, the original group dev gnome group are not doing active development.
  • teamspeak 15 is closed source, with a freemuimum category. The install process is manky 16 newer=better 17. There are *run files available 18

curl -o /etc/apt/trusted.gpg.d/agp-debian-key.gpg http://download.ag-projects.com/agp-debian-key.gpg
echo -e "deb     http://ag-projects.com/ubuntu bionic main\ndeb-src http://ag-projects.com/ubuntu bionic main\n" > /etc/apt/sources.list.d/blink.list
apt update
apt install blink

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