The evolution of software and hardware technology has also determined big changes in current operating systems, therefore constant development of newer versions. The big problems are when users try to install older software apps on the newest operating systems or when the latest software version does not have the same functionalities as the older ones. There are many situations where incompatibilities get in the way of proper functionality and where they cannot be repaired.
The release of a new version of a certain software platform does not necessarily ask for an upgrade, because usually the latest versions of an application may require the presence of the newest operating system and the computer hardware might not support it. On the other hand, it is possible that the latest version of an application does not have the features of the previous version or shows a higher number of bugs than the older editions.
Web developers and generally programmers don't need the complexity of the graphical interface of a new operating system. Instead, what they are interested in is having their development tools functioning at full capacity on a compatible operating system.
Usually, software companies do not provide access to the older releases and if you reinstall the operating system, the software version you are used to work with might not be available anymore. As a consequence, the existence of older software databases is completely justified. These websites allow you to download both current versions of certain software apps, as well as various older versions. If you need to download older software editions, you could find them on existing databases, like OldVersion.com or OldApps.com for example.
Even if the trend is to update your applications constantly, chances are that you use a software app that, on a new release, would also require a higher processor speed or came bundled with unnecessary plugins. It is recommended to carefully select the development tools you are working with in order to avoid frequent software updates or changes of the operating system.