Image forming apparatus including main casing to which cartridge is attachable and main memory and method of controlling image forming apparatus

An image forming apparatus comprising:

• a main casing to which a cartridge is detachably attachable, the cartridge including a cartridge memory storing therein identification information and type information, the identification information identifying the cartridge, the type information indicating whether the cartridge is a subscription cartridge or a normal cartridge, the subscription cartridge being permitted to be used while the image forming apparatus is in a subscribed state in which a service contract is in effect for the image forming apparatus, the normal cartridge being permitted to be used while the image forming apparatus is in both the subscribed state and a normal state in which the service contract is not in effect;
• a main memory configured to store therein history information, the history information including history identification information, the history identification information being identification information for a previous subscription cartridge, the previous subscription cartridge being the subscription cartridge previously attached to the main casing;
• and
• a controller configured to perform:
• in response to a cartridge being attached to the main casing, (a) reading identification information from a cartridge memory of the attached cartridge as current identification information,
• wherein the controller is configured to further perform, after receiving a cancellation instruction for placing the image forming apparatus in the normal state:
• (b) determining whether the current identification information read in (a) matches the history identification information included in the history information stored in the main memory;
• and
• in response to determining in (b) that the current identification information matches the history identification information, (c) permitting use of the attached cartridge.