I am very new to DOT.net frameworks. Shouldn't we always update to the latest release? List Entity framework or identity framework .. all those frameworks ... why do we keep them around? just use the latest ones.
In fact, I am just starting to develop an asp.net website with RestAPIs, login, register, social login... I wonder what is the best framework version (4.5) to use
From a large company point of view. You can not always technically get the latest version of .NET on your servers that store your applications. For some you have to go through a series of procedures to get everything to the latest so it's not necessarily developers that can trudge through this when you have a separation of duties like developers, system admins, etc. Although it's highly suggested to use the latest and greatest. Every dev/company has their own way of actually getting the most up-to-date versions of pretty much anything.