I have Webster's Spanish-English Dictionary (http://www.logos.com/products/details/2006)
On my computer, it displays perfectly. On the iPhone the pronunciation font displays as a series of boxes. In Logos 3 the font used was SIL Doulos IPA. On Logos 4 it appears to be the same.
Does anyone know if the iPhone app is supposed to display this correctly?
I enclose some screen captures to illustrate.

