silli
Even if you questioned whether it was an "attack" of some sort, why not simply go to your appstore directly to see if there's an update to be performed? I understand not wanting to follow a link from a pop-up, but generally, the updates via the appstore would be credible.
EDIT: not certain it shows as an actual update...however, Pixel confirmed that this is a legit pop-up, malware will NOT be downloaded.
