Said of a program or feature that is considered obsolescent and in the
process of being phased out, usually in favor of a specified replacement.
Deprecated features can, unfortunately, linger on for many years. This term
appears with distressing frequency in standards documents when the
committees writing the documents realize that large amounts of extant (and
presumably happily working) code depend on the feature(s) that have passed
out of favor. See also dusty deck.
[Usage note: don't confuse this word with ‘depreciated’, or the verb form
‘deprecate’ with ‘depreciate’. They are different words; see any dictionary