Feel puzzle about the changes in exam format and syllabus

Hi, i know that there is a change in exam format for dec 2014, I am taking the paper in jun 2015 for the F5 paper, may I know is there any change in the version of textbook, exam format for june 2015? Can i refer to the current version of textbook?

Can someone reply me as I do not know whether this should be the time to buy the current version of textbook or to wait for the new version of textbook?