While the BBC will be keeping the iPlayer service free, they will soon be moving to a mandetory account registration via their BBC accounts (it is currently optional). No formal date has been set for this transition, but it will be happening soon. The main reason for the transition is to provide better user experiences by offering personalisation, but there is an alterior motive and that is making sure you are paying your TV licence.
The move will start with the web site and mobile apps, connected tv’s and set top boxes will follow in due course. This is not new news, it was first announced that this process would happen last year when the so-called “iPlayer Loophole” was closed. Previously you required a licence for watching Live TV channels, however this was extended to cover the on-demand content as well.