If you would like to preserve the modified timestamps on your files as you migrate them into Egnyte, you have the following options:   

Sync

Sync apps automatically preserve timestamps when uploading from your computer or storage device.

Web UI

The Redesign of the Egnyte UI preserves the date in uploaded files when uploading via drag-and-drop or browsing for files on your computer. 

FTP

Most FTP clients have an option to preserve timestamps of files that you upload using the client. Our help articles contain a section with setup instructions for several clients popular with our customers.