Whew! https://sustainable-rails.com is now updated for Rails 7.1, but with more substantial changes. Still the same general vibe and messages, but just a bigger update than usual.
If you bought from me, you should've been emailed with the udpate.
If you bought the Kindle version—you should get an update, but I'm not sure how that works.
If you bought from PragProg, the update there is in progress, so stay tuned.
If you have been waiting to buy on the Kobo store or iBookstore - now you can :)