It's almost six months to the day of your post and no indication of an upcoming "B" model. The JA618A is fanless. The "B" models only addressed fan noise, so there's no real reason to change models unless some redesign is required, IMO.
In the case of the 24 & 48-port "A/B" models, which I own both of, the As fans were unnecessarily loud. The Bs are perfectly quiet. I swapped in Noctua fans into the A models to solve the noise issue. Otherwise, they perform identically in every other aspect.
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Travis McMurry
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