According to an embodiment, a communication device includes a version storage unit, a receiving unit, a determining unit, and a command processing unit. The version storage unit is configured to store therein the first version information. The receiving unit is configured to receive a command including the second version information. The determining unit is configured to determine whether a version represented by the second version information is a next version after a version represented by the first version information. The command processing unit is configured to, based on a determination result of the determining unit and decision information that defines processes corresponding to a command and the determination result, execute processes corresponding to a received command.