"Don't call yourself developer if you know only one programming language"
"Don't call yourself developer if you don't know (put any algorithm here)"
"Don't call yourself developer if you don't (have this one particualr skill that I have)"
Nothing changed.
"Don't call yourself developer if you've never built and sold a house".
In the US we mostly haven't done this, so you end up with all kinds of ridiculous job titles with engineer added on. This is probably exactly what will happen with the term developer, and we'll have to move on to using something else.
You can't call yourself a "professional engineer" unless you are one but if you have a CS degree you can actually become a "professional software engineer" if you go through the process, pass all the tests and meet all the requirements.