According to several cases, a failure to notify the opponent of trial renders a judgment only voidable:
A lack of notice of a trial setting, although it might cause the judgment to be voidable, does not render the judgment of the trial court void. Reiss v. Reiss, 118 S.W.3d 439, 443 (Tex. 2003)[incorrect analysis]; Rollins v. Beaumont, No. 05–04–01859–CV, 2006 WL 2100278, at *1–2 (Tex. App.–Dallas Sept. 1 2005, no pet.) (mem.op.) (rejecting argument that failure to receive adequate notice of hearing caused trial court’s judgment to be void); Flores v. Flores, No. 04–10–00118–CV, 2011 WL 3610428, at *2 (Tex. App.–San Antonio Aug. 17, 2011, pet. denied) (mem.op.) (concluding lack of notice does not necessarily void trial court’s judgment because due process requires only that method of service be reasonably calculated, under the circumstances, to apprise interested parties of proceeding and afford them an opportunity to present objections)[implying that if the method is not reasonably calculated, it would be void]; Morse v. Black, No. 03–08–00785–CV, 2009 WL 2476686, at *2 (Tex. App.–Austin Aug. 12, 2009, no pet.) (mem.op.) (same).
In re Lowery, 05-14-01509-CV, 2014 WL 8060585, at *1 (Tex. App.—Dallas Dec. 18, 2014, no pet.)