And no. After May 15 v0.6.2 is not safe to use.
But can I install the 8 version while still having the 6 version? Will there be any conflicts?
You'll need to exit 6 to install 8. 8 will overwrite 6.
If you want to be safe, yo ucan copy the qt folder that contains 6 to another place so you can run that if your install of 8 fails. That's what I did.
I'd recommend you do it before you head to sleep. That way your computer can sync up while you're in bed. It takes Fing forever.