I think Our Family Wizard is a great resource for any set of coparents, particularly those in high-conflict divorce. If you have ever found yourself in an ongoing argument about who said what (and when) with your ex, I think you'll find the app extremely helpful. It can also be used by lawyers, mediators, counselors, and other professionals to simplify and/or monitor client communications.
I used with my ex-husband for the initial (postdivorce) year at the suggestion of my therapist, who often heard about the stress and resentment that was building in our relationship as we attempted to navigate life as parents after divorce. We both kind of scoffed at the idea initially, but it certainly taught us how to communicate in healthier ways.