Something that is obsolete is no longer needed because something better has been invented. So much equipment becomes obsolete almost as soon as it's made. no longer useful, because something newer and better has been invented out-of-date (past participle of obsolescere )
An obsolete element or attribute is one for which there is no guarantee of support by a user agent Obsolete elements are no longer defined in the specification, but are listed for historical purposes in the changes section of the reference manual
old; no longer in use or valid or fashionable; "obsolete words"; "an obsolete locomotive"; "outdated equipment"; "superannuated laws"; "out-of-date ideas"
Stamps which are not available for sale through the post office, though continuing to be valid for postage Stamps which are no longer valid are declared to be 'invalidated' or 'demonetized'