Is there a practice to announce Rosh Chodesh (Birkat HaChodesh) on the preceding Shabbat, and what is its status?

Synopsis

The Magen Avraham, Mishnah Berurah, and Aruch HaShulchan all address the custom of announcing the day(s) of the upcoming Rosh Chodesh on the preceding Shabbat. The announcement is not equivalent to the ancient beit din sanctification but serves an informational function.

Early Acharonim
Late Acharonim
Lenient
Strict
Lesser cited
Major authority

Discussion

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