Therefore, I downloaded CommandPrompt.Activities & used execute single command activity. Then simply input the Command Line.
In my case, excelcnv in Program Files folder, below is the command line.
“”“C:\Program Files\Microsoft Office\root\Office16\excelcnv.exe”" -oice ““C:\file.xls”” ““C:\file.xlsx””"
Thanks for the reply. I did rename the extension manually & use move file activity to rename it. The excel file would be corrupted. For my case, it is essential to convert it as this excel file will be uploaded to Power BI & it only accepts .xlsx file, plus, currently I’m using workbook write range activity in my workflow but the activity behaves incorrectly (you can look into my post, Workbook Write Range: Problem with .xls, for more details).
I just realized you said in your post that this is a tutorial, but you put it in Help/Activities. We thought you were having a problem and asking how to fix it.