I dont think Mendix 4 is still supported, so finding info on that will proably be hard.
In my experience Mendix always provides upgrade guides with all relevant info. I normally find them by using google:
“mendix migration 5 to 6”
leads to this for example: https://docs.mendix.com/refguide6/moving-from-5-to-6
I hope this helps.
Documentation 4.7 is no longer available. Maybe Mendix support can help you?
Dough if you consider upgrading, Mendix 6 is supported until Mendix 9 is released. Expected in the Q1 of 2021
If you have the time and resources, you probably better of moving 7.23, 8.6 or 8.12 is are the supported production releases. https://docs.mendix.com/releasenotes/studio-pro/8.12#8120