Since 15.20 one gets a pop up: "TeamViewer plan upgrade required. Your current TeamViewer plan does not include connections to customized TeamViewer modules. Your session will therefore terminate after a short time. Please upgrade to a higher plan to use this functionality".
It times out in about 5 minutes. No good for supporting friends and family. I have to keep 15.19.5 around on their PCs to continue to support them.