A team under the leadership of Professor Anders Winroth is working on new editions of the two recensions of Gratian's Decretum with support of the Andrew W. Mellon Foundation, Yale University, and the Stephan Kuttner Institute of Medieval Canon Law, and with the assistance from the Yale University Office of Digital Assets and Infrastructure. The new editions aim to replace Emil Friedbergs 1879 edition of the second recension through a fresh collation of the most important manuscripts and a reconsideration of Gratian's sources (both material and formal). The finished edition will be published in the series Monumenta iuris canonici, published by the Kuttner Institute and the Vatican Library. An English translation is also planned.
All information and working materials here.