Although Microsoft released a convenience rollup for Windows 7 which is like Service Pack 2, that includes most of the post-SP1 security updates, non-security updates and hotfixes by request, they gave no instructions on how to make Windows Update work properly after the rollup has been integrated using DISM. Let's see what you need to do to create up-to-date ISO of Windows 7 with updates up to April 2016 so Windows Update works after you install it.
Every time you do a fresh install of Windows 7, even if your ISO file has Service Pack 1 integrated, it takes ages to install all available updates. So, reinstalling becomes a nightmare for those who use the genuine installation media of Windows 7 SP1. Microsoft has decided to change this situation and has released a convenience rollup for Windows 7 SP1 which will save your time.