Communication Device, Non-Transitory Computer-Readable Recording Medium Storing Computer-Readable Instructions for Communication Device, and Method Executed by Communication Device

A communication device may send a first negotiation request including first version information to a first external device via a communication interface of the communication device, execute first communication with the first external device via the communication interface by using the predetermined communication protocol of the second version, send a second negotiation request including second version information to the first external device via the communication interface in a case where an error notification is received from the first external device in the first communication, and execute second communication with the first external device via the communication interface by using the predetermined communication protocol of the first version.