It is likely, that this posthuman condition will be a non-biological one - unless having a conscious experience of the world is unexpectedly tied to being a biological entity.
We can not preclude this possibility as of yet and this issue might even be the central flaw of current transhumanist - and especially singularitarian - thinking.
Certain factors, such as the "visitation" of Earth by alien biological entities in the last few millenia (by now quite well-founded through numerous sighting reports and archaelogical coincidences), might indeed even point in this direction.
Why would biological alien entities visit this planet, if non-biological sentience is the superior form of existence ?
Only time might give an answer to this particular question.
All good points!