A computer-implemented method for selecting one or more upgrade campaign specifications from a given set of upgrade campaign specifications which upgrade a system from a current configuration to a target configuration, the method comprising: - for each upgrade campaign specification: identifying software and management operations specified in the upgrade campaign specification for upgrading the system; and for each of a set of one or more scenarios defined in terms of operation execution time selection and execution mode, simulating upgrade of the system according to a corresponding arrangement of the software and management operations using a Discrete Event System Specification, DEVS, Suit Simulator, thereby obtaining a corresponding execution time and a corresponding outage, wherein the set of one or more scenarios include one of best case scenario and worst case scenario, wherein in the best case scenario each operation performed according to a given upgrade campaign specification succeeds at a first attempt, wherein each operation executes for a time period equal to a lower bound time value specified for the operation, wherein in the worst case scenario each operation performed according to a given upgrade campaign specification fails until a last attempt of allowable retries, and wherein each operation executes for a time period equal to a timeout value specified for the operation; and - rejecting a subset of the upgrade campaign specifications for which the corresponding execution times do not meet an execution time threshold or for which the corresponding outages do not meet an outage threshold. - for each upgrade campaign specification: identifying software and management operations specified in the upgrade campaign specification for upgrading the system; and for each of a set of one or more scenarios defined in terms of operation execution time selection and execution mode, simulating upgrade of the system according to a corresponding arrangement of the software and management operations using a Discrete Event System Specification, DEVS, Suit Simulator, thereby obtaining a corresponding execution time and a corresponding outage, wherein the set of one or more scenarios include one of best case scenario and worst case scenario, wherein in the best case scenario each operation performed according to a given upgrade campaign specification succeeds at a first attempt, wherein each operation executes for a time period equal to a lower bound time value specified for the operation, wherein in the worst case scenario each operation performed according to a given upgrade campaign specification fails until a last attempt of allowable retries, and wherein each operation executes for a time period equal to a timeout value specified for the operation; and identifying software and management operations specified in the upgrade campaign specification for upgrading the system; and for each of a set of one or more scenarios defined in terms of operation execution time selection and execution mode, simulating upgrade of the system according to a corresponding arrangement of the software and management operations using a Discrete Event System Specification, DEVS, Suit Simulator, thereby obtaining a corresponding execution time and a corresponding outage, wherein the set of one or more scenarios include one of best case scenario and worst case scenario, wherein in the best case scenario each operation performed according to a given upgrade campaign specification succeeds at a first attempt, wherein each operation executes for a time period equal to a lower bound time value specified for the operation, wherein in the worst case scenario each operation performed according to a given upgrade campaign specification fails until a last attempt of allowable retries, and wherein each operation executes for a time period equal to a timeout value specified for the operation; and - rejecting a subset of the upgrade campaign specifications for which the corresponding execution times do not meet an execution time threshold or for which the corresponding outages do not meet an outage threshold.