Opkg is a lightweight package management system based on Ipkg.
Here is a list of additional features compared to Ipkg.
Q. What version of Ipkg is Opkg based on?
A. It is based on the ipkg-0.99.163 tarball
Q. Why "fork" and rename Ipkg?
A. Ipkg is no longer actively maintained and there may be issues with using the Ipkg name