CrossOver (known before version 6.0 as CrossOver Office) is the collective name for three commercial and proprietary programs developed by CodeWeavers that allows many Windows-based applications to run on Linux, Mac OS X and Solaris using a compatibility layer. The programs include CrossOver Mac, CrossOver Linux and CrossOver Games.
The programs are tweaked, proprietary versions of the public Wine source tree with various compatibility patches added, more user-friendly configuration tools and commercial support. CodeWeavers employs several Wine developers and contributes code back to the free software/open source software Wine project as per the GNU LGPL, although CrossOver itself is proprietary software.
A second public beta version of CrossOver Mac was made available for free download on September 28, 2006, and a third on November 15, 2006.
A limited 60-day trial of Release Candidate 1 was released on December 22, 2006. A final version was released January 10, 2007.
CrossOver Linux is offered in two versions - Standard and Professional. CrossOver Linux Professional provides enhanced deployability and manageability features for corporate users. The Standard version allows a single user of a single machine. The Professional version allows multiple users.
A full list is available from CodeWeavers’ website.
CodeWeavers has also designed an interest gauging system on their website where one can "donate" money towards a particular application in order to encourage the development team to focus their attention on it and make it fully compatible.