i dont know, what the next beta supported, but i know, that in the 1.5 you could say, what renoise does with midi sysex data and you could, for example, send hardware synth editors thru Renoise to change the filter or such a thing or if only set the synth sound.
Could you activate it again ?
Renoise 1.5 probably didn’t blocked them either, but maybe violetpow has changed something in the MIDI bus-structure that the sysex messages are not send through the MIDI THRU connections but through an IN or OUT?