Well, I am afraid, we cannot help you much regarding your older version that you using. Neither we could provide you the javadocs of any version which is older than one year or so, it is our internal policy not to provide versions, docs or fixes for older versions, we have to abide by our policy.
However, you may try to change your sample code like following if it works fine:
e.g
Sample code:
String w_path = “D:\1.xlsx”;
Workbook w_book = new Workbook();
w_book.open(w_path, FileFormatType.XLSX);
We highly recommend you to kindly upgrade to our latest versions or newer APIs set. We have made tremendous enhancements and supported new features over the years to make the product more robust and feature rich APIs.
It is good to know that your issue is resolved with the code suggested by Amjad. Let us know if you encounter any other issue, we will be glad to look into it and help you further. Have a good day.