Archive - Originally posted on "The Horse's Mouth" - 2008-11-21 05:32:50 - Graham Ellis
Some (but not all) Open Source products have a numbering system where the second number is even for a production release and odd for a development release - so if you're looking to install one of these products on a live machine for customer use, you should make sure you stick with the even release even if a later odd one is available.
Open Source software has an active developer community, and the mechanism requires that there is considerable exposure given to upcoming releases for things to be added, comments made, and code tested and improved by that community, with anyone welcome to play his / her role. For this reason, you'll see a wide variety of extra releases on all open source software that's almost completely absent from commercial software. Commercial software's upcoming releases need to be kept rather private to give the authors their commercial edge, and also to ensure that orders for the current release don't dry up when potential customers say "I won't spend my money on this version - I'll buy the next one when it comes out".
You may still see Apache httpd 1.3, and Perl 5.004 and 5.005, around from time to time. In each of these cases the odd number release was a production version prior to the adoption of the "odd/even" scheme. Apache httpd 1.3 in particular is now extremely mature, but also very commonly used indeed as people don't like to upgrade a web server that's working perfectly well. "If it ain't bust, don't fix it"