If I read these scriptures correctly, the Holy Spirit is there forever. The Holy Spirit is always true and it remains with you and in you.
John 14:16
And I will ask the Father and he will give you another helper to be with you forever,
John 14:17
the spirit of the truth, which the world cannot receive, because it neither sees it nor knows it. You know it, because it remains with you and is in you.
Governing Body Member Jeffrey Winder explains how Jehovah reveals understanding of the scriptures ''new light'' in modern times. Does he quote these scriptures? Nope! He tries to weasel the Governing Body away from all the failed doctrines and blames God with gradual flip-flops and only gradual understanding.
'' So, this is what we know from the scriptures and from our own experiences as well, about how the light gets brighter in modern times. It comes about by means of the Holy Spirit, through his channel of the Faithful and Discreet slave. He reveals it gradually and at a time it is needed.''