You don't mention what you are upgrading to.
If you are installing Design Extender, the following extensions should be uninstalled first:
-- CSS Sculptor
-- CSS Menu Writer
-- Framework Builder
-- PowerCMS Builder
-- Pro Maps for Google
-- Site Import
-- Site Sculptor
-- Social Media Toolkit
If you are installing Data Bridge, you will need to uninstall these extensions first:
--CSS Button Styler
--CSS Form Builder
--DataAssist
--Digital File Pro
--Dynamic Connections
--Dynamic Dropdowns
--Dynamic Web Charts
--Form Toolkit
--HTML Editor
--Image Resizer
--SecurityAssist
--Universal Email
--Validation Tooltips for Spry