Server and non-transitory computer-readable storage medium storing computer-readable instructions

1. A server comprising:

memory; and

a controller configured to:

in a state where first combination data is stored in the memory, receive a first request from a first external device, the first combination data including first account data and first device-identification data in association with each other, the first device-identification data identifying a first communication device, the first request including second account data different from the first account data and requesting replacement of the first account data associated with the first device-identification data in the first combination data with the second account data;

in response to receiving the first request from the first external device, determine whether priority assigned to the second account data included in the first request is higher than priority assigned to the first account data associated with the first device-identification data stored in the memory;

based on a determination that the priority assigned to the second account data included in the first request is higher than the priority assigned to the first account data associated with the first device-identification data stored in the memory, replace the first account data stored in the memory with the second account data included in the first request, thereby storing the second account data in the memory in association with the first device-identification data; and

based on a determination that the priority assigned to the second account data included in the first request is not higher than the priority assigned to the first account data associated with the first device-identification data stored in the memory, not replace the existing first account data stored in the memory with the second account data included in the first request.

2. The server according to claim 1 , wherein:

the first combination data further includes first authentication data in association with the first account data and the first device-identification data,

the first request includes the second account data and the first authentication data, and

the controller is further configured to, in response to receiving the first request from the first external device, determine whether the priority assigned to the second account data included in the first request is higher than priority assigned to the first account data associated with the first device-identification data included in the first request.

3. The server according to claim 1 , wherein the controller is further configured to:

in a case where the first account data is for providing a first service and the second account data is for providing a second service different from the first service, determine that the priority assigned to the second account data is higher than the priority assigned to the first account data; and

in a case where the first account data is for providing the second service and the second account data is for providing the first service, determine that the priority assigned to the second account data is not higher than the priority assigned to the first account data.

4. The server according to claim 3 , wherein:

the first service does not use user data, the user data to be input by a user of the first communication device, and

the second service uses the user data.

5. The server according to claim 4 , wherein:

the first service does not use the user data and uses application data relating to an application program installed on a terminal, and

the second service does not use the application data and uses the user data.

6. The server according to claim 4 , wherein:

the first service transmits notification data to an application program using application data, the application program having been installed on a terminal, the application data relating to the application program, the notification data indicating that a remaining life of a particular consumable item used in the first communication device has reached a threshold; and

the second service provides automatic ordering and delivery of a spare consumable item in response to the remaining life of the particular consumable item used in the first communication device having reached the threshold.

7. The server according to claim 1 , wherein the controller is further configured to:

before the first combination data is stored in the memory, receive a second request from the first communication device, the second request requesting registration of the first communication device with the server;

in response to receiving the second request from the first communication device before the first combination data is stored in the memory, store second combination data in the memory, the second combination data including third account data and the first device-identification data in association with each other;

in a state where the second combination data is stored in the memory, receive a third request from a second external device, the third request including the first account data and requesting replacement of the third account data associated with the first device-identification data included in the second combination data with the first account data; and

in response to receiving the third request from the second external device in the state where the second combination data is stored in the memory, replace the third account data stored in the memory with the first account data included in the third request, thereby storing the first account data in the memory in association with the first device-identification data.

8. The server according to claim 7 , wherein:

the second external device is different from the first external device,

the third request includes the first account data and location data of the second external device, and

the controller is further configured to:

store the first account data, the first device-identification data, and the location data in the memory in association with each other; and

based on the determination that the priority assigned to the second account data is higher than the priority assigned to the first account data, provide a replacement notification to the second external device using the location data stored in the memory, the replacement notification indicating that the first account data associated with the first device-identification data has been replaced with the second account data.

9. The server according to claim 7 , wherein the third account data is used for providing a third service in which the third account data is not used.

10. The server according to claim 9 , wherein the third service transmits second data to the first communication device, the second data being obtained using first data received from a terminal.

11. The server according to claim 1 , wherein the controller is further configured to, in response to receiving the first request from the first external device and based on a determination that the priority assigned to the second account data included in the first request is higher than the priority assigned to the first account data associated with the first device-identification data stored in the memory, in a state where the first combination data and third combination data are stored in the memory, the third combination data including the first account data and second device-identification data in association with each other, replace the first account data associated with the first device-identification data stored in the memory with the second account data, and not replace the first account data associated with the second device-identification data stored in the memory with the second account data.

12. A non-transitory computer-readable medium storing computer-readable instructions for a server, the computer-readable instructions comprising instructions to implement:

in a state where first combination data is stored in a memory, receiving a first request from a first external device, the first combination data including first account data and first device-identification data in association with each other, the first device-identification data identifying a first communication device, the first request including second account data different from the first account and requesting replacement of the first account data associated with the first device-identification data in the first combination data with the second account data;

in response to receiving the first request from the first external device, determining whether priority assigned to the second account data included in the first request is higher than priority assigned to the first account data associated with the first device-identification data stored in the memory;

based on a determination that the priority assigned to the second account data included in the first request is higher than the priority assigned to the first account data associated with the first device-identification data stored in the memory, replacing the first account data stored in the memory with the second account data included in the first request, thereby storing the second account data in the memory in association with the first device-identification data; and

based on a determination that the priority assigned to the second account data included in the first request is not higher than the priority assigned to the first account data associated with the first device-identification data stored in the memory, not replacing the existing first account data stored in the memory with the second account data included in the first request.