A short BBC Africa report, with the headline: 'Islamic State strengthens ties with Boko Haram':http://www.bbc.co.uk/news/world-africa-32435614

Name changes then.
Boko Haram is a nickname, given to it by Nigerians when it was formed in 2002...its official name Jama'atu Ahlis Sunna Lidda'awati wal-Jihad, which in Arabic means "People Committed to the Propagation of the Prophet's Teachings and Jihad".

Islamic State's West Africa Province (Iswap)