User blog comment:Sampop12/Kaito V4/@comment-28951715-20160831124226/@comment-53539-20160901125331

Also, don't forget the original Kato was released in 2006 and not updates until 2011, while Ah software did not update their v2s until recent engine. They were released in 2009.

Unless there is a rhyme or reason to it, updates don't always warrant happening.

Again 3 years is both not a long length of time nor is the engine version tht different enough. Rana, Gachapoid and Gackpoid are examples of update I'd argue about what they add.