So, how do you get the most up-to-date version of Cygwin? Just download the Cygwin Setup program by following the instructions here.The setup program will handle the task of updating the packages on your system to the latest version.The home page for the Cygwin project is https://cygwin.com/.There you should find everything you need for Cygwin, including links for download and setup, a current list of mirror sites, a User's Guide, an API Reference, mailing lists and archives. Parts are GNU software (gcc, gas, ld, etc...), parts are covered by the standard X11 license, some of it is public domain, some of it was written by Red Hat (or the former Cygnus Solutions) and placed under the GPL. You don't have to pay anyone to use it but you should be sure to read the copyright section of the FAQ for more information on how the GNU General Public License may affect your use of these tools.
This includes configuring and building most of the available GNU or BSD software, including the packages included with the Cygwin distribution themselves.
If you are looking for the version number for the whole Cygwin release, there is none.
Each package in the Cygwin release has its own version.
For a searchable list of packages that can be installed with Cygwin, see https://cygwin.com/packages/.
The Cygwin Setup program is designed to be interactive, but there are a few different ways to automate it.You can find documentation for the individual GNU tools typically as man pages or info pages as part of the Cygwin net distribution. Note that when we say "free" we mean freedom, not price.