Editing Forward compatibility (section)

==Not upwardly compatible<span class="anchor" id="NUC"></span>==
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Some products are not designed to be forward compatible, which has been referred to as NUC (not upwardly compatible). In some cases this might be intentional by the designers as a form of [[vendor lock-in]] or [[software regression]].

For example, a cubicle producer considers changing their cubicle design.  One designer promotes changing the footprint from {{convert|4|foot|m|sigfig=3}} square to 1.2 meter square.  Immediately, the sales manager calls "NUC" and the problem is understood: if the footprint changes and existing customers are considering buying more from the producer, they will have to fit a different sized unit in an office designed for the 4 foot <!-- just converted --> square cubicle.

[[Planned obsolescence]] is a type of upward compatibility, but rather than adopting a policy of backwards compatibility, companies adopt a commercial policy of backwards incompatibility so that newer apps require newer devices.