[pphysch]

It seems unreasonable to expect anything that relies on "version:latest" to not break upon a major version change.

What makes a tutorial different than any other software process, in this context?

Your tutorial was written and functions for a particular version of a software. Pin that version. It's the straightforward thing to do.

Frankly, I would be insulted if I was miseducated by a tutorial that purports to be up to date, but was actually written for a old major version. Learning obsolete techniques, missing best-practices.

[bscphil]

Right. The closest analogy I can think of is answers on Stack Overflow. Usually those answers apply to the latest version of whatever software they're about, but this means many of them will eventually be out of date. You can find plenty of answers with code that assumes Python 2, written by authors who had no idea there was going to be a Python 3.

And that's okay. It's not a bad thing for answers to sometimes go out of date.

A really good answer might specify the major version of software it references, just to be future proof, but that isn't strictly necessary since anyone can just add a new answer and old answers can be edited (on Stack Overflow). For tutorials, it's much more incumbent on them not to mislead users into following an old tutorial, since most people will want to start with the latest version. Put a banner at the top that says "this is a tutorial for Flask 2.x, the latest version of Flask at the time of writing", and/or pin versions in your installation instructions.