Seems the "software defined" in these things are mostly about reconfiguring antennas and radio beams. It's perhaps a bit more than a traditional SDR, after all there's not much modern radio communication not using SDRs, even the Mars rovers and satellites have them.
According to the press release, it is just a spaceborne SDR together with a very configurable antenna array, which can be used to provide various kinds of communication links.
But I think the space industry tries to communicate something other than SDR when they are talking about software-defined satellites. E.g., satellites as a service, allowing different customers time share a satellite and use it for different purposes by making the capabilities wider.
Can the satelite in question grow software defined optics and look at things?
Can it grow software defined manipulators and fix an other satelite?
Can it grow a software defined solar sail?
If the answer to these is no then what makes it different from a spaceborne SDR? (And for the record ain’t nothing wrong with that.)