It is important to add, after acknowledging that Muslims have nothing to do with this season as a festive period ( i.e., there is no *odun* in the sense of *eid* ), no special nafilah gathering and no new clothing, it is haram to celebrate the new year as a festival, haven said all that, please note that it is not haram to verbally wish someone a *happy new year 2024* for official purpose or in an official setting with mixed identities (not faith based). It is also not haram to answer such greeting in such circumstance. It is a way of saying "I wish you a prosperous time within the space of 2024". This is applicable to our daily morning prayer "Oh Allah, I ask you the blessings of this day.." regardless of the name of the day. We are also good to say and reply "Good morning", meaning "I wish you a happy morning", "a happy day, "a happy Saturday", "a happy weekend"... all these are prayers in form of wishes, applicable to spaces of time. This does not attach us in any way to Janus of January or Moon of Monday.
Another example in Yoruba is:
Aku *amojuba odun tuntun* yii o, a o ri ire nibe o...etc, this is an acceptable greeting, especially in an official atmosphere where the gregorian calendar is used, like in Nigeria. *Odun* in the context of all the said examples would mean "year
عام"
and not "festivity or eid عيد".
But if someone says " *Aku Odun o* ", then a Muslim can honourably say, emi o se odun o, because *odun* in this context means eid. As Muslims, we only say *aku odun* in our two known eids, not even on hijrah day. We only say "aku amojuba odun tuntun" on hijrah day.
All said, in our interpersonal greetings as Muslims, the scholars discourage us from even saying "happy new year 2024...". What is best is that the Ummah should say such greeting only for Hijrah calender. But don't insult those who say " *happy new year* " to you, or *aku amojuba odun tuntun* , since *odun* here means *year* and not *festivity* .
The Shari'ah is much concerned and more strict about the latter.
Jazakumullahu khayran.