The Cygwin DLL currently works with all recent, commercially released x86 32 bit and 64 bit versions of Windows, starting with Windows Vista. For more information see the FAQ.
NOTE: As previously announced, Cygwin version 2.5.2 was the last version supporting Windows XP and Server 2003. (Instructions for obtaining that version)
Current Cygwin DLL version
The most recent version of the Cygwin DLL is 2.8.2. Install it by running setup-x86.exe (32-bit installation) or setup-x86_64.exe (64-bit installation).
Use the setup program to perform a fresh install or to update an existing installation.
Note that individual packages in the distribution are updated separately from the DLL so the Cygwin DLL version is not useful as a general Cygwin distribution release number.
Support for Cygwin
For all Cygwin-related questions and observations, please check the resources available at this site, such as the FAQ, the User's Guide and the mailing list archives. If you've exhausted these resources then please send email to an appropriate mailing list. This includes observations about web pages, setup questions, questions about where to find things, questions about why things are done a certain way, questions about the color preferences of Cygwin developers, questions about the meaning of the number 42, etc.
Please send notification of technical problems (bad html, broken links) concerning these web pages to the Cygwin mailing list.
Please do not send personal email with "quick questions" to individual Cygwin contributors. The Cygwin mailing lists are the places for all questions. Really. I mean it.