It is from my understanding that starting fall 2017, CMS will have a different curriculum than it currently has. Right now, subjects are divided into different courses: cmcb, biochem, physiology etc. Starting 2017 there won't be division of courses anymore, instead medical students will study "medicine" all together. Current BMS students take about half of the courses as M1's do, and won't repeat the courses later on. This no longer will be possible for BMS Fall 2017 because first year medical eduction, with the new curriculum can't be split like it does right now.
As for as BMS students entering Fall 2016, their curriculum will look same as now; meaning they will take half of the courses as medical students entering fall 2016. But when they matriculate for 2017 medical school, the courses they had taken during 2016-2017 academic year will no longer reflect 2017's version of medical education. They won't be necessarily repeating the courses since they won't be offered anymore. I don't think anyone at this point knows what the curriculum for BMS entering fall 2017 will look like. I will update this post if I find out anything new or more accurate information.