The introduction of meant that the Windows kernel would refuse to load any driver that was not digitally signed by a trusted certificate authority. This effectively killed off many older dongle emulators. The X64 version of Multikey was a monumental engineering effort to create a driver stable enough for 64-bit kernels. Version 18.0.3 specifically addressed stability issues in the 64-bit environment, ensuring compatibility with the stricter memory management of modern Windows operating systems.