It would be nice to know whether these SQL functions are still to be avoided (the manual has long said "do not use"), and if so, why; or whether they have been brought back into usage and the manual is outdated.
The corresponding API functions have no warnings, so I expect that they at least are safe.
They are safe to use, it's just that we want to extend the family of these functions and change them slightly. When we change them, the old variants will stop working and queries that depend on them will have to be updated to use new functions.
Thanks Adam. That simplifies the picture a lot. The manual seems unnecessarily alarmist then, but...
Sonething I haven't thought enough about before is the problem of substantially changing a function (or a class) without also changing its name. A recipe for disaster! I bet this problem even has a name itself.