As an update, reports came out today that the two will be releasing their new song on August 1. Regarding this rumor, YG Entertainment stepped up on July 27 to say, "It is correct that Bobby and Song Min Ho are preparing a new song, but they have not yet decided on the date of release. We cannot even reveal yet whether the two are releasing a solo song each or a collaborative song." In the end, the agency, in true YG style, gave more questions than answers.
So it might not even be a sub-unit! Stay tuned for more information.