Not necessarily! In most cases students shouldn't have to go back over anything they've previously completed, however you still want to keep an eye on what is being changed in earlier sections. Sometimes updates start at the beginning of the syllabus and it takes us a while to work through the end, so checking all updates means you'll have an idea of what's coming and can ask for advice or plan accordingly before the updates get to the section you're on.
You don't have to worry about earlier modules, however, unless an announcement is posted saying that the changes will apply to everyone.
And as always, if you see a change and aren't sure what, if anything, you need to do about it, send me an email or give me a call! I'll be able to let you know exactly what you should be doing.
-Glenda (andi@andrewsschool.com 405-721-3560)