Hi Sarah,
I didn't attend the event in London but I were at a similar event the day before in Belgium where Jim Stone, the global PM for MapInfo Pro, showed a prerelease of the new "ProViewer". I think the name is still to be decided.
So, basically it isn't available yet.
The plan is to have it ready later this year - hopefully.
I'm sure @Jim Stone? and @Andrei Veselov? are happy to elaborate on this.
Maybe this could also be a good place for you and other to tell a bit about what you'd like to see in the new "ProViewer".
Our thinking right now is that it will be a limited edition of MapInfo Pro where at least editing is turned off and potentially also other more advanced features.
Were you happy with the way the 32 bit ProViewer worked? Were you missing specific features? I'm not guaranteeing that will be include those but we are open to feedback.