After some early issues, 8.1 seems to work OK. I particularly like the IMAP support for email that I don't want to hold locally. Bits is GMail for example.
I keep 6.7.4 because it can index RSS feeds. And was better at "confederated" searches until the release of 8.1.
Resources don't need to be an issue. 6.7.4 is mostly dormant. I give it time to index when it won't get in the way of other things.
So I suggest not allowing 8.1 to remove 6.7.4 – it will offer – but do allow it to stop 6.7.4 from launching at startup.
As soon as you are happy with 8.1, then remove 6.7.4.
I keep 6.7.4 because it can index RSS feeds. And was better at "confederated" searches until the release of 8.1.
Resources don't need to be an issue. 6.7.4 is mostly dormant. I give it time to index when it won't get in the way of other things.
So I suggest not allowing 8.1 to remove 6.7.4 – it will offer – but do allow it to stop 6.7.4 from launching at startup.
As soon as you are happy with 8.1, then remove 6.7.4.