Instructions for upgrading from 1.2 to 1.4?

I’m running a really old version (Asterisk 1.2.5) and I’d like to upgrade to a current version and thought I’d upgrade to the 1.4 branch while I’m at it.

I can’t seem to find any documentation on what changed from 1.2 to 1.4 and what needs to be addressed during the upgrade (e.g. changes to dialplan, etc).

Could someone point me to a documentation page or two that I missed?

Thanks!

Download the 1.4 src, in the docs directory there is a file called UPGRADE.txt
It tells you what changed.

Why break a system that is working? Do it on another box or a VM.