1.5 is new fare vending machines that are up to modern standards with software and payment protocols (including accepting contactless) and new tap targets on existing fare gates which accept new tappable charlie tickets, which are already rolling out at certain stations. Lastly the new FVMs can dispense charlie cards. But all the other benefits of 2.0 are missing: payment onboard vehicles with contactless, web management of charlie accounts, server side payments, all door boarding, etc.
So, great, all of the new GLX stations will be front door only. Fantastic.