Substitution has been reimplemented in the meanwhile, where the fresh variables are resolved locally. So there is no global counter for fresh variables anymore as shown in the video, and fewer variable renamings take place.

When calling krun on the programs in lesson_1, a different path is shown than in the README.md.

Marking the beta-reduction rule with [anywhere] will give us the conventional lambda-calculus. A new lesson has been added, 2.5, showing that. The README.md file should be changed at the end to point to lesson 2.5.