Today I did try it, 8600 records with no problems, I did it based on my experience because there was not enough guidance in the import page, by the way the extension files which located in the original repo does not work so i tried your unofficial repo files and it worked perfect.my procedure was:
1- create an items file in excel for example with the following headers
type,item_code,stock_id,description,category,units,dummy,mb_flag,price,dimension
2 - add all your items
3 - save it as CSV file
4 - use import function on FA.
thats it.
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