How to support iOS Timezone override for my iOS calendar app?

I did some RnD on iOS calendar application to check behavior on iOS timezone override enabled. My conclusion on it... 1. iCal (iOS native app) changes its event time according to time zone set in system preferences. Means fully support for iOS time zone override features.

2.Other Calendar App not changes event time for any time zone value set in system preference for iOS time zone override features.

3. In My calendar app if i set time zone value other from my current time zone than no event fetch except all day event.

Plz help me on this if possible. Thanks in advance dear.... :)

Time zone override enable stpes: Go to Iphone Settings > Mail, Contacts, Calendars > Scroll down to Calendar > Timezone Override > Switch it ON