For those who observe י"ט שבט, how is davening affected?
I am aware that Tachanun is omitted, but is it also omitted at mincha on erev Yod-Teth Shevat?
Is Psalm 20 recited at shacharit?
Is hallel recited? If so, is it said with or without a berakha?
Is there an al hanisim or ya'aleh v'yavo addition to shmoneh esrei and/or birkat hamazon? If so, does accidentally omitting it require shmoneh esrei and/or birkat hamazon to be repeated?
I am not planning on confirming what I learn here with my rabbi, so please make sure that your answer is correct.