The mitzvah of Shemittas Kesafim comes into effect this year immediately before Rosh Hashanah. This law cancels all debts that someone is owed, meaning that the creditor cannot force collection.
About Bein Hashmashot, the impact on important mitzvot, how will it affect the time of the bris? Dovening Minha, Shabbat, Rosh Hashana, the Gra and Rabbeinu Tam.