Is sunsetted a valid word?
Initially I though "no way!" but according to Wiktionary it is commonly used as a verb in business to refer to the retiring of a product (why one wouldn't say 'retiring' or 'phase out' is beyond me).
sunset (third-person singular simple present sunsets, present participle sunsetting, simple past and past participle sunsetted)
(business, politics, transitive) To phase out. We'll be sunsetting version 1.9 of the software shortly after releasing version 2.0 next quarter.
http://en.wiktionary.org/wiki/sunset#Verb
This meaning of sunset is in the OED:
to subject to, or terminate by means of, sunset legislation,
meaning that a law which is "sunsetted" is only valid for a certain period of time unless it is explicitly renewed. If this is the definition that was meant, to say that an application "is sunsetted" means that it has an expiration date, after which it no longer works, or is not supported, or is not guaranteed to work.
I believe the past tense used for this meaning is generally "sunsetted" and not "sunset", but I wouldn't be surprised at either one.
The discussion on this is fascinating. Some bemoan "sunsetted" as jargon. I find it refreshing that legal types and computer programmers would use such a delightfully metaphorical term rather than something much duller, e.g. phased out or retired. I also agree with the argument above that "sunsetting" generally caries the meaning of the end being preplanned. Even from this practical vantage point, the allusion to the setting sun seems apropos to me.