I have seen similar questions in the past but not directly related to FluentFtp NuGet package.
How can I keep the last modified date from the sender to the receiver when I am uploading a single file?
Looks like the default is not to preserve it, is there anyway of doing it manually?
FluentFtp won't do it for you. You have to code that yourself. Use
FtpClient.SetModifiedTime:But first, make sure your FTP server supports it. Check if any GUI/commandline FTP client can preserve timestamps of the uploaded files on your server.