TCJA is clear about this.  If no other language was added, deduction should still be allowed.

(c) Effective Date.—The amendments made by this section shall apply to—

(1) any divorce or separation instrument (as defined in section 71(b)(2) of the Internal Revenue Code of 1986 as in effect before the date of the enactment of this Act) executed after December 31, 2018, and

(2) any divorce or separation instrument (as so defined) executed on or before such date and modified after such date if the modification expressly provides that the amendments made by this section apply to such modification.