With respect, until this is substantiated, I would treat it with some considerable scepticism.
It would not make sense to announce the increase in mileage awarded separately from any further announcement of an increase in redemption rates.
Further, it is unlikely that an increase would happen immediately; even with the recent onbusiness changes, there was a "grace period" where old redemption rates would be honoured.
There is no track record for this sort of behaviour in any FF plan. None.