Question: how to change last update date of file?
Answer: Download and Install Attribute Changer here. [00:15]
Right click the file you want to modify and click "Change Attributes". [00:29]
Check the "Modify data and timestamps" box. [00:33]
Use the arrow keys to move time forwards or backwards. [00:42]
Click "Apply" and "OK" and you are all done :) [00:48]