It seems Apple hasn't had enough of litigation in recent months, and have filed another suit against HTC this week. The new case, made in the same Delaware court as their March 2010 suit, alleges that HTC impinges on two additional patents on top of the twenty initially mentioned. These are 6,282,646 and 7,380,116, both titled "System for real-time adaptation to changes in display configuration" but granted in 2001 and 2008 respectively.
Two other patents mentioned in this new suit had already been included in the original twenty, but it seems they have been re-included because of spelling errors. Neither company has made any official statement as yet - we imagine they'll come through over the next couple of hours, as the lawyers wake up - but HTC already have a counter-suit in action against Apple's initial claim, alleging intellectual property theft in the other direction.