the latest HST file format for MetaTrader 4

 
I'm trying to decode and convert HST files from MetaTrader 4 (MT4) into CSV format. However, I've encountered issues with the buffer size and struct.unpack errors. I suspect that the file format or data structure may have changed in the latest version of MT4. How can I find information about the latest HST file format or data structure for MT4 to adjust my script accordingly?