iOS9 Glitch

Work-around for iOS9 glitch. This affects both the HP 12C and HP 15C emulators. The problem: When upgrading from iOS8 to iOS9, the "rotating" feature of both apps is no longer supported. Symptom: With default settings, both emulators are locked in "portrait" mode, which produces the "four function calculator" that others have complained about. The fix: Go to iPhone "Settings" and look for the HP 12C or HP 15C. Default settings include "Landscape Lock" set to ON. Set "Landscape Lock" to OFF. This will restore full functionality of the HP 12C and HP 15C calculators. Unintended consequence of this fix: Loss of the "four function calculator" that HP provided for portrait mode.

Cheapskate01 about HP 15C Calculator