No new anime has been officially announced and the Tweet was replaced with one that removed the mention.
Atto’s 2009 Monthly Comic Alive manga has been adapted into 2013 and 2015 TV anime plus two OVAs.
In a deleted Tweet, Akihabara’s Lashibang, a “conveni[ence store] of ‘moe’” that boasts being the largest second-hand shop for otaku goods (figures, other merchandise, official media, doujinshi), Tweet that they have the Non Non Biyori six-volume set with Animate bonus box in stock – adding that the rural comedy is set to be adapted into a third season.