FreePBX Version 13.0 Supports Asterisk 11 as minimum, and PJSip in Asterisk versions 12 and 13.
Supported/Tested *nix Distributions
|Distribution||Date Last Tested||Certified||Tested||Commercial Module Support||Notes|
|CentOS 6||2016-02-08||No||Yes||Yes (Install)||The "recommended" distribution for FreePBX|
|CentOS 7||No||Yes||No||The "recommended" distribution for FreePBX|
|Debian 8.1||2015-07-31||No||Yes||No||Complete runthrough done using 'netinst' ISO|
|Ubuntu 14.04||2015-07-31||No||Yes||No||Run successfully completed several times|
To reduce download and install time, please be aware that of these instructions give you a minimal install. This is enough to provide for basic PABX functionality, but you should go to Module Admin, and select 'Check Online' to download the additional modules after installation. There are approximately 50 additional modules that can be installed.