I’ve seen two versions. My Nusach Sefard (Koren Edition) includes the word יהיה ביום as does Nusach Ashkenaz Sidurim and Yekkes (and the authoritative Siddur of the Gaon Rav Yaakov Emden). Other Nusach Sefard Siddurim, sometimes have יהיה ביום whilst others (including Nusach Chabad) have ביום which is language used by the Rokeach.
It would seem that the two Nusachaos have at their heart the purpose of this line:
- if it’s to announce when Rosh Chodesh will be, which is consonant with also announcing the time in Yerusholayim, then it would seem that יהיה ביום is more appropriate
- if this is an expression of a quasi Kiddush Hachodesh itself that is done some days before (in general) then ביום is more appropriate.
Has anyone come across a discussion on this?
I haven’t has a change to see what the various Nusachei Eidot HaMizrach say.
As it turns out, I just got the Sefer below on Friday! and so I will find some time to see what Rav Adler says.