Since Monarch was brave, i've decided to update my 100 user licence, too. It worked without any Problems. All subscriptions are set to the same date, so this differs from Monarch's post.
I have just upgraded my old v7 to the new v8 type. I participated in the recent Beta testing, and the previous test programme as well - after which I was very generously given a 100-user license (thank you again!).
The new upgraded license appears to have feature expiry dates that are identical to the old v7 license; even the new 'WebApplicationSecurity' entitlement seems to have the same expiry date of 11 Aug 2010.
I've attached the old v7 license (before upgrade), and the new upgraded license (Owner name removed).
edit: I've now installed the upgraded license on my ASG and it indeed shows all the feature expiry dates as 11 Aug 2010.
EDIT BY MODERATOR: Please do not attach your license files on here, as anyone could grab them and use them. Copy and paste relevant areas of file.