How will the transition to RingCT work?

Question

When Monero implements RingCT, how will the transition be handled?

In particular, how will pre RingCT outputs be migrated into outputs available for use in RingCT transactions?

Answer 1

When someone uses a rct transaction, the outputs are necessarily rct. From hard fork 4 (expected in or around march 2017), both rct and non rct transactions will be permitted. From hard fork 5 (expected in or around september 2017), non rct transasctions will be permitted only if they are spending unmixable outputs (ie, the rules for allowing mixin 0 now).

If you want to make all your outputs rct, you should be able to use sweep_unmixable first, then sweep_all. Assuming you do not have a large amount of tiny inputs, that should make your whole balance only in rct outputs.