You are asking two different things.

First of all, it's already in place at many airports, not waiting for next year.

The two things are 1) Yes, you will need a boarding pass to get through Security. You will not need one to be on the other side of security, as anybody arriving will be on the other side of security and not have a valid boarding pass for a flight leaving unless they are making a connection.

2) Yes, the gates will still print boarding passes, but you can not get there THROUGH SECURITY without one. If for some reason you arrive from another flight without a connecting boarding pass and don't have to clear security to get to the gate they can give you one, but if you have to go through security you will have to get the BP before going to security.