The company behind Snapchat got mixed results in its efforts to ax claims in a group of Vaporstream messaging patents at the U.S. Patent and Trademark Office.

The Patent Trial and Appeal Board June 28 upheld the validity of challenged claims in Vaporstream’s U.S. Patent Nos. 9,306,886 and 9,338,111, despite Snap Inc.’s bid to knock them out in light of prior art. Snap had better luck with U.S. Patent Nos. 9,313,155 and 8,935,351—the board found the challenged claims to be obvious and therefore unpatentable.

The board’s rulings are the latest in a legal fight between Snap and Vaporstream...