The understanding of v6 and v9 is the holy grail for me at present, I do not support the download of MQL4 market now, maybe my MT4 has problems, I cannot change dealers, in my country, there is only one broker that supports MT4, and other trading software does not support this indicator, I have changed my computer, VPS and VPN. The terminals on MT4 are not supported, and the ones I purchased before are not supported to download, including changing the mql5 account, and I am trying to log in every day in the later stage, I don't want to miss the Holy Grail for me。I have searched a lot about similar problems, maybe MQL4 or MT4 upgrade problems, you can continue to download later, need to wait