why don't you just test it? Copy it over and do a syntax check.
If there was no difference then SAP would not need to provide different releases.
Of course there are function modules in current system which were not written when 4.7 was launched at the market. When we implemented ECC6 we upgraded as well to Unicode which forced us to change coding in old programs.
There are ABAP commands which have not been there at 4.7 times.
You can't get a clean bill of health for such generic question, you can just test it, and if there is trouble then you need to fix it to make it run.
If you have read some OSS notes for new developed functionality then you could know how rarely SAP offers the option to implement such function in a lower releases.