ZuluTalk

Credits

ZuluTalk exists because of the work of Belledonne Communications and the Linphone community.

Linphone

Linphone is an open-source voice, video and messaging app based on the SIP standard, developed by Belledonne Communications SARL. Linphone is dual-licensed: it is free under the GNU GPLv3, and Belledonne also offers proprietary licenses for closed-source products. ZuluTalk uses Linphone under the GNU GPLv3.

  • Linphone for Android, version 6.2.8: © 2010-2025 Belledonne Communications SARL. Original source. The ZuluTalk repository keeps the full Linphone commit history, so every original author is credited for their work.
  • Linphone SDK, version 5.5.35: the calling engine (liblinphone, mediastreamer2, belle-sip, oRTP, bctoolbox, bzrtp and other components) by Belledonne Communications. Source. ZuluTalk uses it unmodified.
  • Third-party components included in Linphone are listed by Belledonne: Linphone third-party components. Each keeps its own license.

Translations

ZuluTalk's translations are Linphone's, made by volunteers on Linphone's Weblate. To improve a translation, contribute there. It helps Linphone and ZuluTalk.

What ZuluTalk changed

Our changes are small compared with Linphone itself: a new name and icon, calling-only defaults, video limits on mobile data, a video fix for foldable phones, and (from 1.3) removing defaults that use Belledonne's servers for ZuluTalk users' logs and STUN. Each Linphone source file we changed keeps its original copyright notice and has a modification notice added. The full list is in ZULUTALK.md.

Names and support

"Linphone" and "Belledonne Communications" are the names of Belledonne Communications and its product. We use them only to say where ZuluTalk comes from. ZuluTalk is not affiliated with, endorsed or supported by Belledonne Communications. Please send questions about ZuluTalk to reports@zulutalk.com, not to Linphone.

If Belledonne Communications would like anything on this site or in ZuluTalk changed, please write to reports@zulutalk.com and we will change it.

License

ZuluTalk is free software under the GNU General Public License, version 3. You may use, study, copy, change and share it under that license. The complete source code for every release is on GitHub.