Multiple versions of a runtime system, such as a software emulation application that emulates a legacy hardware architecture, are allowed to co-exist in the memory of a new hardware architecture. The operating system software of the new hardware architecture reads configuration data from a database or table to decide which version of the runtime system is desirable for an application program or game that is being loaded or is currently running, and, if a match is found, only that runtime system is invoked. To reduce storage footprint, the different versions of the runtime system may be stored using “differential patching” techniques. In this configuration, the operating system will always launch the same basic runtime system binary, but it will select a different differential patch to apply at run-time based on the title as determined during the database lookup. In this fashion, future changes to the runtime system to correct software bugs, incompatibility issues, and the like only need to be tested for the relevant target application programs or games.