Thanks for reporting this issue! I’ve fixed this, and now the API docs default to version 3.7.x. You can access the 3.7 API docs using either of these two links:
I had to change the version format from 3.7 to 3.7.x, to match the other versions in the drop-down list. Because of that, the link you posted to the 3.7 docs will not work. Sorry for the confusion!