I've seen some code golf languages that still a work in progress (functions being added etc), but they have already been made public and people are posting answers using those languages.
I'd like to know what the standard practice is regarding changes to the language as it's still being polished. Adding functionality is always fine (with the usual restriction for not winning challenges with a posterior version of the language). But what about changing functionality? That would imply old answers would possibly cease to work in the new version. Is that considered acceptable? Should the language designer ensure full backwards compatibility?
As a specific example, suppose a language has function
Xo for producing the number
pi.1 Later on, the designer decides the name
Xo would be better suited for a new function that is going to be introduced. To what extent would it be acceptable to rename the function that produces
pi, and change the meaning of
Xo? "Never do that" / "Try to avoid it as much as possible" / "Only in some cases" / "Don't worry, that happens all the time"... ?
o looks like a circle, and
X is an extension prefix