The latest chapter right now is Chapter 5! You can download this on my Patreon page. If you need help with this, read my FAQ page: How do I download the latest chapter?
For more information, check out the timeline on our home page which explains each chapter and what they contain!
Note: You do not need to download previous chapters to play the latest version of the game. If you played the demo (Chapter 3) and want to play Chapter 5, you do not need to go download Chapter 4. The latest chapter has all content up to that point.