[schr0dinger]

Well minor including the switch to use of so called “quantitative type theory” where you can include use counts for variables that inform the compiler how long variables will stick around. Also the compiler switch to Chez Scheme yields a pretty big performance boost.

[zelphirkalt]

The Idris 2 compiler is build with Chez Scheme? That's pretty cool in my opinion, didn't know that.

[mjepronk]

It compiles to Chez Scheme. It's written in Idris 2 (self-hosted).

[rq1]

It is written with Idris2 as the article mentions.

It produces/translates to Chez Scheme code.

[mx00s]

You're right, there are several notable improvements in Idris2. I was mainly referring to the amount of code from the book that must be adapted. The QTT features, as you say, are opt-in; by default no new constraints are imposed.