I hear kaguya will release new contect for this game on 16th
It's just the last patch the creator did for the Japanese version. Over on his Twitter he said he had sent Kagura the data for it around the start of the year. The sequel starring the sister Yutaka has also been sent to them now and he's currently working on the next (and possibly final) update to that one.
For anyone following along with this creator:
The sequel to Country Girl Keiko is a total remake of his old game Muchi Muchi Inaka with a full new story after the fact and a "true" ending that plugs the looming plot hole at the end of Keiko's story, giving you a full happy ending. It also has an even more dark bad ending that you'd really have to work for.
The next update reimagines the cousin visit from Muchi Muchi School Trip with both of the sisters visiting the cousin with an all new set of time-based game mechanics (according to his most recent Twitter update.)
If you've played Country Girl Keiko you should enjoy the older versions of Yutaka's adventures, they're all listed in other threads and should be accessible via the "similar threads" area near the bottom of this page.