FreePBX Moves to Debian

FreePBX, the web interface most people use to run the Asterisk phone system, is about to make the biggest platform change in its history. FreePBX 17, in beta for months and expected to reach general availability any day now, drops the CentOS-based FreePBX Distro and runs on Debian 12 instead.

For a lot of small businesses, schools and offices, FreePBX is the phone system. The box in the closet that makes the desk phones ring. So this matters well beyond the Linux world, and it's worth explaining why it's happening and what to do about it.

Why now

For years, the standard way to install FreePBX was the FreePBX Distro, more recently called SNG7: an ISO from Sangoma, the company behind FreePBX, built on CentOS 7. You booted it, answered a few questions, and had a working PBX.

CentOS 7 reached end of life on June 30, 2024. No more security updates. And there was no CentOS 8 to move to: Red Hat cut CentOS Linux 8 short at the end of 2021 and replaced it with CentOS Stream, a moving preview of the next RHEL rather than a stable rebuild. A phone system needs a base that holds still and gets security fixes for years. Stream isn't that.

Sangoma's choice of Debian makes sense on every count. Debian stable releases are supported for about five years with LTS. Upgrades between releases work in place. Asterisk and its dependencies are well packaged and well understood on Debian. And Debian is a community project that no vendor can pull out from under you, which is exactly the lesson CentOS just taught everyone who relied on it. I've made the general case in why I prefer Debian.

What changes for administrators

  • No more ISO. FreePBX 17 installs with a script onto a minimal Debian 12 system. You install Debian, run Sangoma's installer, and it adds Asterisk, the web stack and FreePBX.
  • apt instead of yum. Package management, repositories and some file paths are different. Commands like fwconsole that manage FreePBX itself work the same.
  • Newer everything. PHP 8.2 instead of the ancient PHP versions CentOS 7 carried, a current Asterisk, and current versions of MariaDB, Apache and their friends. That's a security improvement on its own.
  • Modules may lag. Some commercial and third-party modules took time to be certified on 17. Check every module you rely on before you plan the move.

How to migrate

There's no in-place upgrade from a CentOS 7 FreePBX box to Debian. You build a new system and move the configuration across. Here's an order that keeps the phones working:

  1. Inventory first. List every module, trunk, extension, inbound and outbound route, IVR, ring group, time condition and custom dialplan in extensions_custom.conf. Custom dialplan is where migrations usually go wrong.
  2. Back up everything with FreePBX's Backup & Restore module, and copy the backup off the box. Back up voicemail and call recordings separately if they're large.
  3. Build the new system on Debian 12, in a VM or on new hardware, with a different IP address, and install FreePBX 17.
  4. Restore the backup onto the new system. Version 17 can restore backups taken on 16. Then fix what didn't come across cleanly and re-check every module.
  5. Test with real calls, on a few extensions, before moving the trunks: inbound, outbound, transfers, voicemail, fax if you still have it, and emergency calling.
  6. Cut over at a quiet time, moving the SIP trunks and registering the phones to the new server. Keep the old server powered off but intact for a week, in case you need to go back.

Plan on a weekend for a small office and considerably more for anything complicated. And don't leave the old CentOS 7 box on the internet while you get round to it. A PBX that's exposed and unpatched is a toll-fraud incident waiting to happen, and those bills are measured in thousands of dollars of international calls.

Why this is good news

It's a disruptive move, and some administrators are understandably annoyed at doing a full migration of something that works. But FreePBX was sitting on an end-of-life operating system with an outdated software stack, and every month made the eventual move harder. Moving to Debian puts it on a base that's current, secure, community-run and likely to stay that way for decades. That's worth a weekend.

Since then

Added October 2026. FreePBX 17 reached general availability on August 2, 2024, two days after this was written, officially supported on Debian 12.