What Nintendo 3DS family of consoles can I transfer to and / or from?

You can transfer from a Nintendo 3DS, Nintendo 3DS XL, Nintendo 2DS to a New Nintendo 2DS XL, New Nintendo 3DS, New Nintendo 3DS XL.

You can also transfer to and from New Nintendo 2DS XL, New Nintendo 3DS XL, New Nintendo 3DS.

You cannot transfer from a New Nintendo 2DS XL, New Nintendo 3DS, New Nintendo 3DS XL to a Nintendo 3DS, Nintendo 3DS XL, Nintendo 2DS.