Redmine

We have used Redmine from time to time over the years with no stability issues.
With the current ROR set up we seem to be getting lots of internal errors from bad form input etc.
Searching for overall Activity will crash the whole system for example.

We are looking for some advice on our set up and help with getting the glitches out, optimization etc so our team and get back to work with out interruptions.

The set up is mysql version 5.5.46-0+deb8u1
Linux 3.16.0-4-amd64
Redmine 2.4.2
puma 2.15.3

We will be paying by invoice as we are an Australian Public company.
email Adam@venturekey.net