Communication with ex about school stuff

We use one of those co-parenting apps to keep things civil but sometimes it feels cold and formal. Had a parent teacher conference at school and they want me and the ex both there. Worried it's going to be awkward or we'll disagree on how to handle our kid's behavior issues in front of the teacher. We usually can talk okay on text but face to face is different. Any tips for keeping things professional and focused on the kids?