@[deleted] I would suggest first to backup current files/database, then1) download the whole osTicket 1.10 package again2) install the database3) do not change any settings, e.g., language, forms, etc4) Make sure you have php 5.6 (e.g., 5.6.28) installed or php 7.0 (not 7.1)5) Make sure you have all php extensions installed (Admin Panel > Dashboard > Information > PHP Extensions)6) Make sure you have date.timezone set in php and you have restarted httpd(apache) after installing packages/making changes to configuration file.If it still does not work, then revert back to previous version. If it does work - introduce changes gradually and see what breaks it. I have seen similar issue when you had previously set profile to use different language file and it broke stuff. Please do note, do not overwrite existing files, move existing files to a different location before trying vanilla installation.That's all I can recommend for you. Other options include installing different OS, but sometimes it is not possible. It is worth noting that I have CentOS 6 and php 7.0 and I have almost no issues at all.