You should be able to afford paying maintenance or renewing annual license, so use the latest SP3 instead. It has more features and is performing better. Also you can't restore a newer backup to older 3CX version, even you have found the image.I want to downgrade. Does 3CX have a page with old versions?
Please put the link.
Thanks
Founded in 2005, when VoIP was an emerging technology, 3CX has gone on to establish itself as a global leader in business communications.