How do I stop receiving updates to upgrade to Firefox 5? It's not compatible with Roboform and I don't want to do that.

I upgraded from Firefox 4 to Firefox 5, only to find out it's not compatible with Roboform. I uninstalled 5, resinstalled 4 and am now receiving updates on a daily basis recommending I upgrade to 5. I want to stop receiving these messages but don't know how to do that. Thanks for your help!