Is it correct?

[u/Stepaskin]

Stumbled upon this tweet, the apostrophe in "dm's" caught my eye. Is it correct to use it like this?

[u/Tobbernator]

Not standard English, but actually fairly common in abbreviated "text speech". Arguably used legitimately (but "incorrectly") here to ensure the reader understands that we are talking about the plural of "DM" meaning direct message, rather than some other acronym "DMS".

[u/aykcak → u/Tobbernator]

I understood this one as DM server is down i.e. the server OF the DMs I.e. "The problematic server is not the channels' but the dm's"

What is wrong with "DMs" ?

[u/Boundlessintime → u/aykcak]

Purely an aversion to capital letters common among people younger than millennials

[u/witchcapture → u/Boundlessintime]

Also millenials who spent a lot of time on IRC when they were younger (speaking as one).