When the Organisation of Islamic Conference did change its name to Organisation of Islamic Cooperation (OIC)?

1. June 28^th, 2011
2. July 28^th, 2011
3. August 28^th, 2011
4. September 28^th, 2011

on June 28^th, 2011,  the Organisation of Islamic Conference did change its name to Organisation of Islamic Cooperation (OIC).