W and H were married in 1980 in Amherst, living thereafter in Massachusetts for approximately ten years. They had two children: a daughter, born in 1985, and a son, born in 1987. In 1990, they moved to New Mexico, and in 1993, to Oregon. They were divorced in Oregon on August 15, 1997. One month before entry of the Oregon judgment, in July 1997, W returned with the children to Massachusetts, and they have continued to live in Massachusetts since that time. Also, in July 1997, H moved to Idaho, where he currently resides. The Oregon judgment awarded shared legal custody of the children and gave W physical custody of the children with reasonable visitation to H. H's child support obligation was $750 per month 'for so long as said child is under the age of eighteen (18) and thereafter for so long as said child is under the age of twenty-one (21) and is a 'child attending school [under Oregon law].'' The issue of college expenses for the children was not addressed in the Oregon judgment, but the parties intended to share those expenses. In March 1999, and in December 2004, W filed complaints in the Probate and Family Court to revise and amend the Oregon judgment with respect to the provision of child support, seeking contributions to the children's college expenses. H moved to on the ground that the Probate and Family Court lacked subject matter jurisdiction to modify the Oregon judgment because the UIFSA allows a Massachusetts court to modify a child support order issued by another State only in circumstances where the person seeking modification is a 'nonresident' of the Commonwealth. The court denied the motion to dismiss. Trial was held, and judgment was entered. H appealed.