Software manufacturers want to sell the most latest (successor-) versions. New software versions shall generate higher revenues. From the viewpoint of the software producer, the software lifecycle is to be terminated as soon as the current version shows a decline in sales. This is the case when most of the market participants have already purchased the current version of the computer program. If a higher net profit is achieved by the release of a successor version, the economically monopolistic software producer will discontinue the version.
In this case the user often only has a recourse to used software, because the old version is no longer sold by the manufacturer.
Used software has been discussed in the legal literature for more than 20 years. “Software is a product that can not be subject to a wear process” , determined Prof. Dr. Thomas Hoeren already in 1992.
With software, no wear phenomena occur in the conventional sense.  A software product possession of which is gained by a second party, is therefore not to be regarded as used in the sense of the word. In practice, however, it has become established to call a software, which is sold to a third party by a first-time buyer, used software. In contrast, the term “new software” refers in practice to software without a prior user. It is to be regarded as new because it is acquired directly from the rights owner or from a dealer, usually a company authorized by the rights owner.
Although software does not wear, used software, in particular standard software, which has already been used by a first-time buyer, is significantly cheaper than new software at the purchase price.
Hoeren, CR 1992, 257, 258.
Hoeren in CR 2006, 573; Rüffler, ÖBl, 11/2008, 52.