I have been unable to find an answer for this. The last spec I seem to find that mentions backward compatibility is 2.1.
They are backward compatible. But - since each version brings new functionalities with it, only the basic function set is backward compatible all the way, see the table for more detail. In addition to that 2 devices wanting to communicate using bluetooth have to support the same profile(s), the full piece that i copy/pasted from here.
protected by Community♦ Oct 8 '14 at 20:47
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