In a not unexpected development, there’s a security and bug fix update for the recently released WordPress 4.4. There is a known exploit in circulation, so you’re advised to update immediately if you haven’t done so already (or indeed if automagic updating hasn’t done it for you).
Full details from the official source:
 While Tiggercam was updated, Losing it wasn’t, due to me having changed the ownership of formatting.php when I was fixing my shrunken smilies. Once I’d reverted the ownership, the update ran as normal