stateDiagram-v2
    [*] --> NOT_INSTALLED
    NOT_INSTALLED --> INSTALLED : skilz install
    INSTALLED --> OUTDATED : registry updated
    OUTDATED --> UP_TO_DATE : skilz update
    UP_TO_DATE --> NOT_INSTALLED : skilz remove
    INSTALLED --> NOT_INSTALLED : skilz remove

    note right of INSTALLED
        SHA a1b2c3
    end note
    note right of OUTDATED
        Registry SHA b2c3d4
    end note
    note right of UP_TO_DATE
        SHA b2c3d4
    end note