Dynamic delivery of code and fixes

A network device distributes, to multiple user devices, a client application that includes multiple modular code segment files and obtains updated code segment files and dependency information for the client application, the dependency information associating known defects in the client application with one or more of the updated code segment files. The network device receives an error report from one of the multiple user devices, the error report including a particular defect identifier, and determines, based on the dependency information, that an updated code segment file is available to correct an error indicated by the particular defect identifier. The network device retrieves, from a code segment storage location, the updated code segment file and sends the updated code segment file to the one of the multiple user devices.