1. A computer-implemented method for detecting impact of an operating system upgrade, the method comprising: detecting a call from a software entity running on a first data processing system to a current operating system of the first data processing system; recording the detected call in a data structure configured to contain one or more recorded calls; scanning an upgraded operating system on a second data processing system upon which the upgraded operating system is installed and running, before execution of the software entity in a run-time environment of the upgraded operating system, to identify the recorded calls in the data structure that fail to be supported by the upgraded operating system; and presenting an indication of the identified calls.