I used to be able to change the theme colours.  Why can't I do that anymore?

Answer:

In version 1.18 I removed the theme colour options from the settings. 

No, there is not an IPhone version of PD Diary.  I am working on getting the code ready to work on an IPhone, but there is a huge obstacle in the way:  I need to have a Mac computer, or laptop to compile the software.  Of course they are not cheap, so I will not likely be purchasing one in the near future.