Hello Sam,
It's really easy to be updated.
You just have to select the right items in your "interest subscription".
Every week, I receive an email with everything that moved on my particular product.
There is probably no patch to got from 6.3 to 6.4 but you have to download the full 6.4 and use the same license file.
This has been discussed a few times here and also recently.
Alfred.