Hi lavanya,
As you will have to appear for May16 exam then refer Supplemet Study Paper (SSP) of FA 2015 which is relevant for May 16 & Nov 16 exams. So if you have any latest reference book then it will covere FA 14 & FA 15 amendments.
So focus more on FA 15 amendments & case laws of ICAI rather than refering FA 14 amendments because most of them already asked in May 15 & Nov 15 Exams so no need to refer FA 14 SSP.
If you have surplus time and only you want to update u rself then refer FA 14, otherwise give enough time for FA 15 SSP and refer it Thoroughly from upcomoing Exam point of view.
Hope you have got it now.
All the best.