If you already have a recent ISO of Ubuntu, you can update it to the latest ISO quickly using zsync. However, if you are stuck with Windows for some reason and need to update the ISO, you can download the new ISO using either the direct download or torrent. However, although zsync is not available in Windows by default, we use Cygwin to get zsync on Windows. By using zsync through Cygwin, you can update the old ISO to the latest one just like in Linux.

To update the old ISO to the latest ISO using zsync in windows, here is what you need to do:

Install Cygwin

Downlaod the Cygwin setup.

Run the setup.exe file and proceed with the installation as usual.

During the installation you will be asked to choose a download source. Pick Install from Internet and proceed with the installation.

After you have picked a download site, you will be asked to select the packages you want installed. The default selection should do fine. Just ensure that zsync is set to install.

Proceed with the installation as usual.

Updating the ISO using zsync

After the installation has been completed, make a folder called Download in C:/cygwin/home/<name>/. (Assuming you installed in the default location.)

Copy the old ISO you have to the folder you have created above.

Now launch Cygwin and go to the Download directory created using the usual cd command.

Now get the appropriate zsync link from http://cdimage.ubuntu.com/daily-live/current/

Then run the zsync command. As an example, if you have to download the 64-bit version, the command would be

zsync http://cdimage.ubuntu.com/daily-live/current/natty-desktop-amd64.iso.zsync

That is it.

You can use it to update any file if the server supports zsync.