How will GTA Online data transfer to PS4?

I know our GTA Online PS3 character and data will transfer to the PS4 version (and not the story data) but how will this be done?

Will we need to keep our PS3 copy of the game? Or will it simply check the cloud for our PS3 save and import our data from their on PS4?

Is there any news on this yet? I'd imagine GTA V will hit PS4 sometime between September and November so we're only 3-4 months away, we should know if we can sell our old copies by now.

I know PS+ uses the cloud save features already between Vita and PS3, PS3 and PS4, and Vita and PS4, so I'd imagine the same PS+ cloud would be used for your question.

Of course, there is no firm details yet as far as how they are going to go about it. Perhaps a USB drive will also be used.

It doesn't even use the PS+ cloud stuff, it is the Rockstar Cloud they've used for awhile now.

AFAIK Xbox platforms will support online character transfers too.