Can FB7 license be used for FB6.x installation?

We already have two users on FB 6.3.0.2172 using our existing Named User license. We just purchased another Named User license, however our purchasing department did not specify that it was to be for the older version. Can we use the new license on the old version? Or are we going to have upgrade our existing license and installations to version 7? And if so, do we have to buy another license package to replace the current FB 6 licenses?

Also, comparing the contents of the old FB 6 license and the new FB 7 license, it appears that we're only allowed a single installation and a single instance of FB 7 instead of the two installations and single instance described on the FB pricing page, am I reading that right?

Tested it and FB 6 did not like the new FB 7 license, went into eval mode So the question now is do we have to buy a new Named User package to upgrade our existing FB 6 users?

FB7 licenses will not work for FB6. Contact support at finalbuilder.com and Dani will sort you out with an FB6 license. We don’t offer prior versions for sale on our store, however you can request an FB6 license once you have purchased FB7. This is only available to existing customers who already have FB6 (which is the case for you).