An issue was discovered on goTenna Mesh devices with app 5.5.3 and firmware 1.1.12. By default, a GID is the user's phone number unless they specifically opt out. A phone number is very sensitive information because it can be tied back to individuals. The app does not encrypt the GID in messages.
https://github.com/Dollarhyde/goTenna_v1_and_Mesh_vulnerabilities