carl
It should do both depending on how thresholds, knees & ratios are set.
Well, not necessarily. All compressors and expanders have those parameters, but they don't necessarily all do upward expansion (decompression) or upward compression (de-expansion), unless they have a dedicated mode or range of values (e.g., postive threshold). However, Dan Warrell did confirm on KVR that Pro-MB will do upward and downward compression and expansion.
carl
There's also a paid update coming for Pro-Q / 2.0.
Really?! Any idea what it will have/do that v1 doesn't?