http://www.getchu.com/soft.phtml?id=943761
http://currant.jp/pricklyash/kannagirina/index.html

Includes a bonus chapter 7. Standalone chapters:
Chapter 1: https://e-hentai.org/g/1042837/7c8a5038cd/
Chapter 2: https://e-hentai.org/g/1042838/c2ecd6b885/
Chapter 3: https://e-hentai.org/g/1042839/7fe227f5bd/
Chapter 4: https://e-hentai.org/g/1042840/7a7b47c3d6/
Chapter 5: https://e-hentai.org/g/1042841/88eb1e8982/
Chapter 6: https://e-hentai.org/g/1042842/f5a2785521/

0009-0226: event
0227-0353: character
0354-0373: background

@Sakiel
Yeah, looks like only this bundle package version has that bonus chapter.

I bought all chapters of this game separately but I didn't get a bonus chapter (chapter 7).
How could I get it, or I need to buy a bundle package version?

Base +6