Is C++ Variant Considered Stable?

[David McCallum]

I'm starting out with Bison and using the calc++ example program as a
starting point. It includes variants (%define api.value.type variant), but
the Bison documentation says that "this feature needs user feedback to
stabilize".

https://www.gnu.org/software/bison/manual/html_node/_0025define-Summary.html#g_t_0025define-Summary

Are there changes pending for variant that might break my parser somewhere
down the road? Or is it considered safe to use?