Asking the creator for the MQ4 file directly.
Before we dive into the conversion process, let's quickly understand what EX4 and MQ4 files are.
Converting a file you didn't write may violate the developer's Terms of Service or Copyright. The Best Alternative: Contact the Developer
If you cannot find the original source code, consider these options: Contact the Developer
Most free decompilers will fail with an error: "This EX4 was compiled with a newer version."