Hello. I just bought a "new other" Samsung GS IV (I-337 AT&T model) off ebay. It appeared to be fully new. I charged the battery to 100%, and then began setting up the phone - migrating and updating apps, etc. It has used about 25% of the battery in an hour. Maybe this is typical for setting up a new phone? Anyway, it made me concerned about what kind of battery life I can expect going forward. I did note that it is android 5.0.1. I may or may not have a problem with battery life, time will tell. However, is it possible to downgrade to 4.4.4 kitkat?