You cannot safely decompile a MetaTrader 4 (MT4) .ex4 file back into an .mq4 source file using "EX4 to MQ4 Decompiler 40432 Updatedl Top" or any similar downloadable crack tools.
MT5 uses a different compilation model. If you are rebuilding an EA, consider rewriting it for MT5 with improved features. ex4 to mq4 decompiler 40432 updatedl top