
Quoting
Mr. Knowitall
If your lawyer and your ex's lawyer both agree, and have both advised you that the prior provision remains in effect, and both of you follow the advice of counsel, then it shouldn't be an issue.
If your ex and his lawyer take the position that the order is now silent, such that IRS rules govern who may claim the exemption, the big question is who is entitled to claim the exemptions under the IRS rules. If it's you, then that would work to your advantage, although it can create complications if both of you claim the exemption for the same tax year. If it's him, you should speak with your lawyer about seeking clarification from the court.