I think this ruling applies only to hyperandrogenic females such as Dutee Chand--not hypoandrogenic males such as Caster Semenya. I think genetic males that want to compete in the female classification still have to conform to an upper normal female hormone level through chemical or surgical means.
The point of the CAS ruling, brought by a Chand appeal, is that genetic females should not be required to conform to an arbitrary upper normal hormone level by chemical means. Hormonal therapy decisions in these cases should be driven solely for medical purposes with the sole purpose of promoting the health of the patient--not to qualify for competition. For any physical or physiological characteristic with a distribution, there will always be outliers, so you cannot penalize or disqualify outliers. In athletics, the Olympians are all outliers in terms of their performance. Also, it is not necessary that the female range of hormones not overlap the male range--just like height of basketball players there are some female players that are taller than some male players--we do not disqualify over 2.00m female players.
I think the IOC got it right in defining a normal female hormonal level for male-to-female transgender athletes, but still needs to define males by genetics (having a Y chromosome) to determine who has to comply and who does not. A genetic male with complete androgen insensitivity will be in the normal female range (or actually below the female range and require a TUE for a little bit of testosterone for health purposes) and have no problem. Caster, with incomplete insensitivity will present female outward appearance from birth, but enjoyed a late/partial male puberty. He/she has to make a decision to compete as a male as is or take hormone therapy to compete with females. It appears she chose the latter, as the reduced male hormone levels has not allowed her to maintain her previous training load and suffered some overtraining injuries. With a reduction in male hormones, it is likely that she will not be able to again achieve a sub-2:00 performance.