I wouldn't bet on this being validated internally esp. with 6.2.5 EOL at the end of 2018.
But you can ask vmware support this and should be able to get an answer.
On the other hand, 6.2.5->7x is a tough migration for complex / heavily customized setups;
again you can reach out to support (or your TAM, if you have such) and ask for help thru this process.
check this page - VMware vRealize Automation – Upgrade Center
