System for tracking code changes when upg

A couple of tips:

1. Place all mods in seperate include files and the include files in their own directory
2. Place comments in the include file describing what it is doing.
3. Place comments around your include file call in the ProductCart page you are modifying
4. Put a text document somewhere with the page name and line number in your old code. Be sure to keep this file updated as you do upgrades if the info changes
5. Document any changes you make to the database.

There are several pieces of software the will do file compares based on the content. Off hand I don't remember specific names well enough to recommend one though.  One suggestion, get a clean install of the version you are now using and run some file compare software to find where your changes are, markup the pages in your version. as suggested by the earlier poster. However commenting the start of the change, the purpose, and date and commenting the end of the modified code right in the page being modified can work too.

P.S. ( a rough approximation) include files are used in the page you are working on, but stored seperately and then referenced with an include statement. the software then in essence pastes the include file into the page you are working on when it is accessed by the browser.