Block II means better and faster processors inside the electronic mission system of the attack helicopter, as well as the digitalisation of older analogue systems such as the video recorder. The renewed chopper got an improved IFF, an electronic system to recognise friends from enemies (foes) on the battlefield, and have improved capability to cross data usage with other friendly units.
All 28 Apaches of the Koninklijke Luchtmacht (RNLAF) will undergo the Block II update. The eight machines based at Fort Hood in Texas for training purposes will be modified by Boeing, the other 21 by the Logistics Centre at RNLAF air base Woensdrecht. The Dutch Ministry of Defence hopes that all Apaches have been upgraded by 2017. The Netherlands flies the Apache attack helicopter since 1997.
Source: NL MoD