PCalc, the iOS app noted for it's wonderful iOS 8 widget, has to be pulled from the App Store, according to Apple. James Thomson, developer of PCalc, has received notice from Apple that the current iteration of PCalc's days are numbered. I'll let him fill you in:
Apple has told me that Notification Center widgets on iOS cannot perform any calculations, and the current PCalc widget must be removed.— James Thomson (@jamesthomson) October 29, 2014
Here's the reason this is a confusing decision from Apple:
And yes, Apple is currently featuring PCalc in the “Great apps for iOS 8” section, under Notification Center widgets.— James Thomson (@jamesthomson) October 29, 2014
PCalc featured on the second row of the Notification Center Widgets section of the App Store.
This is a disappointing move by Apple, reminiscent of the days when Apple would mysteriously reject updates for all sorts of reasons, sometimes similar functionality, and adding transparency with guidelines was supposed to make this easier. Unfortunately it doesn't, because Apple explained it thusly:
I would be allowed to make a widget that let you to “enter a formula” but it couldn’t perform the calculation in the widget.— James Thomson (@jamesthomson) October 29, 2014
To sum up: Apple featured an iOS 8 app because it has a calculator widget. Apple then told the developer to pull the app, because it has a calculator widget. Apparently widgets aren't allowed to do math, because...reasons? There's been no additional explanation, and as of now the app is still available in the App Store.