Official comment
In the current builds of rekordbox (3.x and earlier), the R1 is only supported for using export devices - there is no ability to link over ethernet or wireless to rekordbox. The initial list for hardware supported under rekordbox 4.0 omits the R1 as that list is showing what hardware will be able to use the performance aspects of the software (the "DJ" side).
While all R1 users (myself included) would like the R1 to be able to control rekordbox as a DVS as the other hardware listed could, the initial release will not support it and there is no guarantee it will be added at a later time.
To clarify, the XDJ-R1 will still be supported by rekordbox DJ as it is supported by rekordbox now -- you will be able to prepare your content and export to devices.