1. An information processing apparatus to which an option unit is connectable, the information processing apparatus comprising: a storage unit configured to store update firmware for updating firmware of the option unit; an update unit configured to update the firmware of the option unit by using the update firmware stored in the storage unit; and a setting unit configured to set any one of a first update method in which the update unit updates the firmware of the option unit in both cases where a version of the firmware of the option unit is to be upgraded and where the version of the firmware of the option unit is to be downgraded, and a second update method in which the update unit updates the firmware of the option unit in a case where the version of the firmware of the option unit is to be upgraded and does not update the firmware of the option unit in a case where the version of the firmware of the option unit is to be downgraded, wherein the update unit operates according to the update method set by the setting unit.