Modern MetaTrader builds (Build 600 and higher) use a completely different compilation method. They generate optimized machine instructions rather than simple byte-code.
Since the Build 600 update, decompiling MT4 files has become incredibly difficult. While there are rumors of private services or expensive cloud-based tools that claim to decompile modern files, there is no widely available, free, or reliable software like the old 4.0.432 version that works on current builds. ex4 to mq4 decompiler 4 0 432 16