My hosting company has upgraded to php7 and have given me 30 days to fix errors I am having with my forum version 126.96.36.199. I am hoping that version 2.3 is compatible with php7.
Will I loose everything on my current forum if I upgrade to ver 2.3?
Yes php 7.0 or php7.1 + opcache run fast beutifull,
Php7 is recommended for 2.3
Your version of Vanilla is massively out of date.
Follow the READ ME carefully. I think there is an extra step for forums <2.1
Ideally, you would do the upgrade in a test environment first.
There should be no loss of anything when updating. Vanilla 188.8.131.52 has several known security issues, so you should really update.
There are many discussions dealing with how to update. A backup is the most important thing before you start.
If you have changed any of the core files, you will loose that changes.