Update HST File

Updates automatically when you reference that timeframe.

On MT4: Unless the current chart is that specific symbol(s)/TF(s) referenced, you must handle 4066/4073 errors before accessing candle/indicator values.
          Download history in MQL4 EA - MQL4 programming forum - Page 3 #26.4 (2019)

What do you mean by "reference that timeframe" ?

I've tried accessing the close value of h4 candle but it doesn't update the H4 file. As you can see the file is from 2 days old.

 double CurrentH4ClosePrice = iClose(_Symbol, PERIOD_H4, 1);