I had a child support judgment in New York State. My son and his mother subsequently moved to Connecticut. WE asked Connecticut to assume jurisdiction.

3 months ago, my son and his mother moved back to New York State. Does the jurisdiction automatically revert to New York?

By Connecticut state law, if the child is over 18 and not in high school, support obligations end.

My son is over 18 and not in high school in NY or any other state, nor does he plan to attend high school. Must I maintain child support?

Did you write up a new order, when the new jurisdiction took over ? In law seldom is anything automatic but the child support agreement that is in place is the one the court will rule on.
So the court order ( not current state laws) is what you go back to, if your written agreemement is not in agreement with current state laws, then you may take them back to court to modify

Was the jurisdiction moved to CT? As long as you remained in NY, it should have remained there.

... WE asked Connecticut to assume jurisdiction. ...

What does this mean?

The Connecticut courts assumed jurisdiction for the purpose of

modifying the decree; or
enforcing the decree? Or

the Connecticut child support agency took over the duty of collection?


Unless the support order was modified by the Connecticut courts (so as to extend the period in which support is payable), the original order remains unchanged.


...
By Connecticut state law, if the child is over 18 and not in high school, support obligations end.
...

Is this different from New York law? What does the support order say?

Is this different from New York law? What does the support order say?

Yes NY law goes to 21.