Apple puts off white iPhone 4

Apple delayed the release of the white iPhone 4 for the second time, saying the model is still harder to manufacture than expected.

The white model will be available later this year, the Cupertino, California-based company said today in a statement. The black models are not affected, it said.

Apple sold 1.7 million of the black model iPhone 4, which features video calling, in the first three days after its June debut. That month, the company postponed releasing the white model until the second half of July, citing unexpected manufacturing challenges.

Apple has been contending with criticism over the design of the iPhone 4 antenna, which results in diminished signal strength. Users complained of lost reception when they held it in a way.