First of all. Classic had a end of life years ago. It currently is only supported to upgrade to the current php,Mysql versions such as the 7X series.
So referencing a patch in the 7x version has no relevance for your version.
As I recall over time classic was observed by web hosts as a resource hog. In fact some hosts disabled the script from running at all.
If you are not willing to upgrade, Your only two resources are to either resolve your issues with your host or find a new host for your forum.
I know it sounds curt but it is a fact of life today.
