I want to take F4 exams this September 2020 but I have Kaplan Book+Kit valid from September 2016 to 31-August-2017. Should I buy updated or is it still valid for coming exams?
As per previous posts regarding material my advise is to obtain a more recent edition especially as there have been changes to some of the commercial laws in particular insolvency.
You will find that a lot of the material overlaps with the new material but there has been some changes in legislation over the past 4 years and therefore the risk is that you are learning some areas of law which are now out of date.