Let me put the disclaimer first that I am probably the least qualified person to advise on renewals as I have not yet received my first pre-approval 
That said, there is a set of official PDFs on the SEF website listing out required renewal documents for each GV route. For example, the standard property route renewal list can be found here (English version):
Now my understanding is that for renewals you’d just get on your usual SEF ARI portal and book your renewal biometrics appointment. There is apparently no online pre-approval involved hence no need to submit the scans in advance online.
Hope this is helpful for what it’s worth.