The Windows 8 Upgrade Advisor

If you run the upgrade advisor it flags EW V4 as one of the items for you to review and says there's an update available.

The link it gives takes you to the normal Microsoft Expression Web page with no mention of any upgrade.

Bottom line? You can ignore this warning. EW will work as normal

Installing a fresh copy of EW V4 on Windows 8

If you install EW V4 on Windows 8 you'll probably do so from the basic version, ie with no service packs installed. (Although some download versions may include the service packs).

When Windows 8 next runs Windows Update, or maybe you run it manually, it doesn't find SP2 as being available for EW.

The solution for this is to download and run the version created to fix licencing issues, mentioned on the Expression Forum and in this Knowledgebase article.

http://support.microsoft.com/default.aspx?kbid=2635101

This includes SP2 so once you've installed this you have the latest version of V4.

Note that there is another fix mentioned in a general article about licensing and activation issues, although I can't verify that this works. See:

http://support.microsoft.com/kb/960480/en-gb

 

NOTE: The free download version will also fix the licensing issues BUT will negate any support options you may have with your purchased version of Expression Web.