Yad ha-Rav Nissim has published many important books, but for the past few years they've been quiet. This morning I saw a new and very important publication, which came out just a few days ago. It is a new edition of Mahzor Aram Zova, with an extensive introduction by several scholars. I don't remember all the details of Mahzor Aram Zova - I believe it represents a European (Spanish?) rite brought to Syria by Jewish immigrants, and that it was published only once, in a very rare and today incomplete printing. See here.