Complex sentence: Regular supplements have been signed between the Mainland and Hong Kong governments, including Supplement VIII (also referred to as CEPA VIII), which was signed on 13 December 2011 and implemented from 1 April 2012.
Split into simpler sentences: Regular supplements have been signed between the Mainland and Hong Kong governments. The most recent, Supplement VIII (also referred to as CEPA VIII), was signed on 13 December 2011 and is implemented from 1 April 2012.