Relevant edition of ipc study module

pls somebody tell me relevant edition of ipc study module for ipc group 2 examination going to be held in may 2016, as I have 2014 edition and it is told 2015 edition is relevant and whether only addition, modification as given on the initial pages of each module are the only changes over previous edition and also tell me that 2016 edition isn't applicable for may 2016 exam and the same isn't available for sale at present .