I see you have quite various Asterisk experience and would like to hire you if possible to make some adjustment to existing system.
Task: We have MOR (Kolmisoft) Billing, please see here more: [url removed, login to view]
That is run on Asterisk 1.8
We cannot upgrade Asterisk to 1.11 to allow messages between SIP clients, but have demands to have it working.
Would it be possible to make some workaround on existing Asterisk 1.8 platform with billing on top to enable messaging between SIP clients similar like Asterisk 10 and onward allows to do ?
I will grant remote access to test environment and by end of project you will need to demonstrate that it is working and issue step by step manual how to do the same on production machine.