Yes, except there seems to be a move on the best words from SHALL to MUST and from SHOULD to MAY. IANAL but I recall reading this in e.g. legal language guidance sites.

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aunderscored 2 hours ago | parent [-]

RFC language is expmicltly defined in 2119[0]. Any other interpretation is incorrect.

[0] https://www.rfc-editor.org/rfc/rfc2119

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Alive-in-2025 2 hours ago | parent [-]

Thank you for that. So should is optional, people!

	▲	strken 33 minutes ago \| parent \| next [-]
		Pulling exact quotes out, SHOULD means "there may exist valid reasons in particular circumstances to ignore a particular item" while MAY means "an item is truly optional." I don't think this can be interpreted as simply "should is optional".
	▲	sisve an hour ago \| parent \| prev [-]
		I think that is a bit to easy. MAY is described ar optional. SHOULD - Should really be there. It's not MUST, you can ignore it but do not come crying if your email is not delivered to some of your customers ! you should have though about that before.