Best way to debug MODx?

I have some issues with performance of my website build in modx 2.2.0, what is best way to debug server requests?

http://tara-aid.com/sr/

In the first place you need to upgrade that MODX. That version has known security vulnerabilities.

This is a very nice tool. https://modstore.pro/packages/utilities/debugparser

It is not free, but you can get it free from GitHub and build it yourself without support.

I know about security, but the problem is with performance, I am using shared hosting with php 5.2, apache 2, what version to update???

Is it easy update, that will now broke my website?

Well, PHP 5.2 is a problem all by itself. I don't think later versions of Revo work well with that version of PHP.

Ok what is optimal version of revo for PHP 5.2