Have you already checked documents about:TalendHelpCenter:Upgrading+your+Talend+products and TalendHelpCenter:Compatible+Platforms+and+Java+environments?
What we can do is to make sure that Talend will be your best choice!
Yes i did look through it. My doubt is :
talend version 6+ uses java 1.8
while version 5* uses java 1.7
and version 4* uses java 1.4?
How does one move a talend job from version 4 to version 6?
Looking forward to your answer.