Keeping Internet Drafts "active" with two updates per year is a subversive tactics, but apparently already in use: Version 02 and 04 of the pack URI drafts are identical. This draft cannot be published as RFC, because its proposed URI scheme syntax is in conflict with the generic syntax in STD 66 [RFC 3986]. This is not permitted in BCP 115 [RFC 4395] about the registration of URI schemes, as noted by the URI review expert.
The pack scheme has to be fixed before it can get a permanent registry entry. The current entry is provisional, and the unmodified draft could be an attempt to prevent the reclassification of this wannabe-scheme as historical. The greater picture is that the Open Packaging Convention is a part of ECMA 376, the fast track input for ISO 29500 also known as ooXML.