This post is obsolete. For the most recent on version checks in 2015, please visit:http://opensourcegisblog.blogspot.com/2015/03/foss-gis-version-checks-march-2015.html.
Keeping software up-to-date is extremely important. Open source GIS software is no exception. Typically, updates bring fixes, stability (fewer crashes), sometimes security patches, and/or even new features. Many people who use a computer or (mobile) device never really think about updating or upgrading the software--unless the software informs them of an update. Still, a user may chose to ignore these messages and be unaware of the benefits.
Updates for-fee/paid software are also important and sometimes may require you to update your license agreement depending on when you purchased the software, what version you own, and when the update was released.
On the other hand, a user may not know that an update has been released after the first installation. IT folks may also rely on a GIS analyst to inform them of the latest updates. Do not assume your IT person keeps track of all of the software and updates on your computer. Also, you may need their help if do not have installation privileges. Some software is updated frequently, while others are updated annually.
So, after today's post be sure to have the latest (stable/released) version of the following! Keep in mind they may be updated, so keep an eye on their website or subscribe to their e-mail listserves. These are the best ways to keep up-to-date. Here's a quick list of a few open source GIS programs, their version numbers, and release date.
Grass GIS: Version 6.4.2 (Feb 2012)
Quantum GIS: Version 1.7.4 (2011)
Opticks Image Processing: Version 4.9 (May 2012)
GeoDa: Version 1.0.1 (Oct 2011)
Fusion LIDAR: Version 3.10 (May 2012)
Many open source GIS programs have a roadmap or 'wiki. These sources of timely information can give you the heads-up on when an update will be released and what features the new version may contain. Lastly, they often contain lists of bugs and potential fixes.