Losing your customizations on upgrade can be an annoyance. Often the upgrade instructions say to overwrite the templates simply because this is easier for most people, who haven't changed a lot. If you have extensive customizations, perhaps you would prefer a line by line list of the exact differences between your template and the new one, so that you can make the neccesary adaptations.

For WSN Knowledge Base 4.1.0+, the upgrade tool should provide you with links to file comparisons for the updated templates which you've customized.

Otherwise, for WSN Links, a tool is available for you at http://www.wsnforum.com/filecomparison/comparison.php

For alternative easier-to-read output, you can also download a free file comparison program: http://www.prestosoft.com/ps.asp?page=edp_examdiff . This program will take the two files (your template, and the new template) and show you line by line where the differences are.

If you're a Linux user, use Kompare instead. It comes pre-installed on many distros, if it isn't you should check your package manager.