There are new complaints, since the Google search app was updated, that it doesn't work with iOS 6 devices.
The Google Web Search Help forums has many of those complaints and they have increased since the updated Google Search App came out yesterday. The issue turns out to be on iOS 6 jailbroken devices. So I assume it is not a huge population, because:
(1) Most people have upgraded to iOS 7 and
(2) How many are running iOS 6 and a jailbreak?
That being said, the Google Search App does not open, it completely crashes, if you are running iOS 6 jailbreak.
Forum discussion at Google Web Search Help.