Dear Andrei,
> I think, yes, version of pg_stat_statements is need to be updated. Is
> it will be 1.10 in PG15?
I think you are right.
According to [1] we can bump up the version per one PG major version,
and any features are not committed yet for 15.
[1]: https://www.postgresql.org/message-id/20201202040516.GA43757@nol
Best Regards,
Hayato Kuroda
FUJITSU LIMITED