Deltarune creator Toby Fox says the game’s fourth chapter is now being bug-tested on PC 

Fresh from reminding people on X about his Sans and Reigen Arataka cartoon, Undertale creator Toby Fox is back with another Deltarune update. This time, Fox announced via Bluesky that Deltarune Chapter 4 is currently being bug-tested for PC. 

In true Toby Fox fashion, the update post is in cartoon format and features the in-game sprite of Jockington, one of Kris’s classmates in Deltarune. As mentioned in his Halloween update and backed up by a recent Bluesky post, Fox is “100% certain” that Deltarune Chapter 3 and 4 will release in 2025. 

Following the bug test update, Fox comments that he is not sure when the next Undertale/ Deltarune newsletter will come out. These are emails sent to people on the Undertale/ Deltarune mailing list, usually regarding the progress of Fox’s ongoing projects. Instead, Fox explains that he will give small updates as development on Deltarune progresses.  

Deltarune Chapter 1 was released on macOS and Windows on October 31, 2018 before being ported to the Nintendo Switch and PlayStation 4 on February 28, 2019. Deltarune Chapter 2 launched on macOS and Windows on September 17, 2021, with the Nintendo Switch and PlayStation 4 versions following six days later on September 23, 2021.  

Since Deltarune is made using GameMaker Studio 2, an engine that requires either a macOS or Windows operating system, there is a high chance that Deltarune Chapter 3 and 4 will launch on these platforms first before being ported to others. 

Deltarune Chapter 3 and 4 are set to be released sometime in 2025.