A computer-implemented method for deploying upgrade packages during a zero downtime upgrade of a production software system, the method being executed using one or more processors and comprising: initiating and at least partially conducting a zero downtime upgrade of the production software system for moving from a first version of an application on the production system to a second version of the application on a target system; testing the target system; determining, based on the testing, whether any corrections are needed, wherein if no corrections are needed and the zero downtime upgrade procedure is complete, the method comprises transitioning the target system to production; wherein if corrections are needed the method comprises the further steps: receiving, by the one or more processors, an upgrade package, the upgrade package defining one or more changes to be deployed to the system, and comprising one or more objects having respective object types; receiving, by the one or more processors, a deployment configuration, the deployment configuration providing a plurality of lists of object types and, for each list of object types, specifying a deployment option for object types in the respective list of object types; reviewing the upgrade package in view of the deployment configuration by determining, by the one or more processors, a set of object types included in the upgrade package, the set of object types comprising one or more object types; and selectively permitting, by the one or more processors, deployment of the upgrade package to execute the one or more changes based on the set of object types and the plurality of lists of object types, wherein selectively permitting deployment of the upgrade package comprises: determining that the upgrade package includes at least one black-listed object type, and in response, rejecting the upgrade package for deployment, otherwise determining that the upgrade package includes one or more grey-listed object types; and deploying the one or more grey-listed object types using an extension to a standard deployment procedure, wherein the extension is provided in the deployment configuration, and determining that the upgrade package includes one or more white-listed object types; and deploying the one or more white-listed object types using a standard deployment procedure. initiating and at least partially conducting a zero downtime upgrade of the production software system for moving from a first version of an application on the production system to a second version of the application on a target system; testing the target system; determining, based on the testing, whether any corrections are needed, wherein if no corrections are needed and the zero downtime upgrade procedure is complete, the method comprises transitioning the target system to production; wherein if corrections are needed the method comprises the further steps: receiving, by the one or more processors, an upgrade package, the upgrade package defining one or more changes to be deployed to the system, and comprising one or more objects having respective object types; receiving, by the one or more processors, a deployment configuration, the deployment configuration providing a plurality of lists of object types and, for each list of object types, specifying a deployment option for object types in the respective list of object types; reviewing the upgrade package in view of the deployment configuration by determining, by the one or more processors, a set of object types included in the upgrade package, the set of object types comprising one or more object types; and selectively permitting, by the one or more processors, deployment of the upgrade package to execute the one or more changes based on the set of object types and the plurality of lists of object types, receiving, by the one or more processors, an upgrade package, the upgrade package defining one or more changes to be deployed to the system, and comprising one or more objects having respective object types; receiving, by the one or more processors, a deployment configuration, the deployment configuration providing a plurality of lists of object types and, for each list of object types, specifying a deployment option for object types in the respective list of object types; reviewing the upgrade package in view of the deployment configuration by determining, by the one or more processors, a set of object types included in the upgrade package, the set of object types comprising one or more object types; and selectively permitting, by the one or more processors, deployment of the upgrade package to execute the one or more changes based on the set of object types and the plurality of lists of object types, determining that the upgrade package includes at least one black-listed object type, and in response, rejecting the upgrade package for deployment, otherwise determining that the upgrade package includes one or more grey-listed object types; and deploying the one or more grey-listed object types using an extension to a standard deployment procedure, wherein the extension is provided in the deployment configuration, and determining that the upgrade package includes one or more white-listed object types; and deploying the one or more white-listed object types using a standard deployment procedure.