Sister-Honoring one’s older sister:
Some Poskim rule that a person is not obligated in the honor of his older sister even if she is the firstborn. Nonetheless, even according to this opinion, he should show her extra respect and not talk before she does. However, other Poskim rule that one is obligated to show respect also for the firstborn sister as well as all the sisters who are older than him, and so is the ruling according to Kabbalah.
 See Encyclopedia Talmudit ibid p. 469 footnotes 1293 and 1296
 Beis Lechem Yehuda 240:12; Shvus Yaakov 1:76; Pischeiy Teshuvah 240:19; Maharam Shick Mitzvah 33
 Birkeiy Yosef 240:17; Chikrei Lev Y.D. 2:7; Derech Pikudecha 33; Yad Shaul 240:15 in name of Chacham Tzvi in manuscript who wrote a dissent on the Shvus Yaakov; Ben Ish Chaiy Shoftim 2:28; Torah Temima Yisro 86; Cheshbono Shel Mitzvah of Adart 33
 Arizal in Shaar Hamitzvos Parshas Yisro, brought in Birkeiy Yosef 240:17 and Shut Rav Yedidyah ibid