> On 29 Dec 2024, at 09:57, John C Klensin <john-ietf@xxxxxxx> wrote: > >> I think that there are two levels here and this is where the term >> fails: >> >> 1) the protocol is done, and extensions are unwelcome. >> (keep using it as you prefer). >> >> 2) the protocol is unsafe and not only should you not extend it, >> but you need to plan to stop using it. > > There are at least two more: > > 3) The protocol is obsolete and no one cares any more but, while > there is nothing inherently unsafe about it, we advise against its > use. Example: there is nothing fundamentally wrong with RFC 594, at > least if one has a working IMP floating around (but those devices > are, themselves, Historic). > > 4) The protocol specification has been superceded by newer > specifications but the document is still identified as Standards > Track (sometimes even Internet Standard) and there is nothing unsafe > about it (at least any more so than the successor documents). > >> In most cases we mean (1), but the industry hears (2). > > Except when we mean (3) or (4) -- or should be using some variation > on "Historic" but have not bothered -- in which case "the industry" > just gets confused and maybe questions either our sanity or > willingness to take responsibility. In software releases, all four of these cases would be covered by the term "deprecated". Jay > > john > -- Jay Daley IETF Executive Director exec-director@xxxxxxxx
