Answering to this depends on what obsolete means to you. Merriam-Webster defines it as “no longer in use or no longer useful”, which are rather different criteria. A word might not be in general use anymore but it might be useful to talk about the past, e.g. in books or conferences about the history of a certain field. My favourite example is the Spanish word lansquenete, which is a straight borrowing from German Landsknecht and refers to a German infantry soldier during the reign of the House of Habsburg. This is a doubly obsolete word since the vast majority of Spanish speakers don't know it and it can't really be used anymore, nor is it really needed. Yet it's not marked as obsolete in the DLE (the dictionary of the Real Academia Española) because it still has a place in the parlance of historians, in historical novels, period pieces, etc. On the other hand, there was once in the DLE a word cocadriz, designated the female of the crocodile (cocodrilo); it was removed from the dictionary because it was truly obsolete: no-one used it anymore in any way, apparently, as far as the lexicographers could determine. Yet it seems that very few words get removed in this way; many are saved by being used in the classics (something like if Cervantes used a word twice, then it stays in the dictionary forever). I'm giving examples from Spanish because it has (and has had for a while) a more or less centralized language authority. With most other languages, determining whether a word is obsolete or just very infrequent depends on who gathers the textual corpora and studies the frequencies of words and which criteria they use. More on reddit.com

I'm not sure it's obsolete. We also say "turn the lights out," "the power is out," "cut it out," "school's out," and so on. More on reddit.com

That's not so bad. I once heard a guy say "deepcreated" like 5 times on the same day even after correcting him. Depreciated makes more sense at least More on reddit.com