I have made one application in which I implemented ePub reader which unzips file and parses xml file. I have adopted method of this question on S.O. Reading ePub format .
The code was working fine till today before I replaced .ePub files with client's updated files. After replacing .ePub files I ran application on simulator and I was shocked as ePub reader shows all file's content in BOLD format randomly, I mean assuming there are 5 .ePub files in application sometimes it shows file 2,3 content in BOLD sometimes file 1,4,5 content in BOLD. I could not figure out the problem so I replaced those files with older ones and problem disappeared..
Following the apple guidelines http://support.apple.com/kb/HT4168. I recommended client to use Pages '09 to export ePub files. So is it the problem with coversion using Pages '09? because I have opened all .ePub files in stanza and calibre and contents were not in BOLD format. So I can't figure out wether its a conversion problem or coding problem.
Code I used for reading ePub files(Maybe it will help): http://pastebin.com/dY4CFetU
Thanks..