I'm just scratching the surface for VoIP with Elastix. I notice that Elastix 2.x is "open source" but 5.x is proprietary?

Looking into licensing from the manual on Elastix brings:


I don't want to get entangled with some sort of lock-in. Rather, the flavor of lock-in I prefer has GPL attached to it. Elastix is, or has, moved away from GPL? The version I'm on uses CentOS.

Right now I'm running Elastix 2.x remotely, just wondering whether it's the best choice or will be a licensing dead-end.

Wikipedia reports the licensing as:

License GNU General Public License(2.5) Proprietary (5.0)


Elastix 2.5 is free software, released under the GNU General Public License. Elastix 5.0 is Proprietary released under the terms of the 3CX license


In 2016 the Elastix project was acquired by 3CX. With this acquisition the Elastix Distro versioned at 5.0 was switched to a branded Debian install with the 3CX platform

  • Where did you find the license information for version 2? Is it actually the GPL? There are many varieties of open-source other than that, and it makes a big difference in options for a company to relicense. Commented Dec 28, 2016 at 17:47
  • @XiongChiamiov updated question. see wikipedia.
    – Thufir
    Commented Dec 29, 2016 at 6:19

2 Answers 2


So, let's break down the possibilities here.

Elastix owns some of its own code. It gives you permission to use it under the GPL, but it isn't bound by the GPL itself, because it owns the code. It can do whatever the hell it wants with that code. It can license it to you under the GPL, and sell it to me under a proprietary license, and then stop offering it under the GPL, or whatever. The versions they already offered under the GPL are irrevocably licensed, but they don't need to keep giving that code out.

Then, you have contributors' code. I'm not sure if Elastix took any external contributions -- if they didn't, then this section doesn't matter -- but assuming they did, they really had two options. One, get permission to use those contributions, or two, don't use them. This holds true no matter what their outbound license is.

A lot of GPL projects will take contributions under the GPL. Since the contributions are under the GPL, those projects are stuck using the GPL as long as that code is there. If they want to use a different license, they have to get rid of the code.

Some GPL projects will have Contributor License Agreements. Those agreements can kind of say anything. They can say "all contributors grant us a license but we are required to always offer the project under the GPL." Or, "all contributors grant us a license but we are required to always offer the project under some open source license. Our board of directors will pick the license." Or, they might say, "all contributors grant us a license and we can do whatever the fuck we want with their code." They might even say "all contributors pass their copyright over to us." I'd be willing to guess that Elastix went with option three here -- that's relatively common among CLAs.


Exciting news for the Elastix community. We’re releasing a new version of Elastix powered by 3CX instead of Asterisk. 3CX is an open standards PBX and has built a strong following with frequent updates.

Elastix 5 will be bundled in a special free version of 3CX which includes 8 sim calls (approx. 25 extensions). Integrated into 3CX, free of charge are also smartphone and desktop clients as well as WebRTC-based video conferencing.

3CX has also committed to investing in the Elastix community with free certification, training and forum support. In addition, 3CX is planning on announcing a rewards program for active Elastix community members.

Edgar Landivar, CEO of Palosanto said:
“We were considering a telephony engine switch for some time now. The 3CX PBX is easy to use, open standards and feature rich. With the recent advent of its Linux version, as well as the free PBX edition, it is the perfect choice to power Elastix. The 3CX WebRTC Video conferencing engine is particularly impressive. I believe Elastix users are best served by this decision”

per: https://www.elastix.org/blog/latestnews/elastix-5-powered-by-3cx/

Guess they just took some of the most important GPL components. Weird. I would've assumed someone else would pick up 2.x and fork it. Guess not enough demand.

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