heatseeker

[IBM] n. A customer who can be relied upon to always buy the latest version of an existing product (not quite the same as a member the lunatic fringe). A 1992 example of a heatseeker is someone who, owning a 286 PC and Windows 3.0, goes out and buys Windows 3.1 (which offers no worthwhile benefits unless you have a 386). If all customers were heatseekers, vast amounts of money could be made by just fixing the bugs in each release (n) and selling it to them as release (n+1).