It is impossible to say, because we don't know what your ETL logic looks like. Most likely it is fine. Don't you have an acceptance/uat/test environment where you can try it out? 

It depends upon the older code. We recently went from 9.3 to 13.3 and then from 13.3 to 14.3 we did face some issues with the code. 

The changes if required are very basic, unless you land in issues with performance blockers. So you can try giving one run in Dev/QA environmentthen see the altitude of the changes if any required.