https://docs.timescale.com/about/latest/release-notes/

This release moves all internal functions from the _timescaledb_internal schema into the _timescaledb_functions schema. This separates code from internal data objects and improves security by allowing more restrictive permissions for the code schema. If you are calling any of those internal functions you should adjust your code as soon as possible. This version also includes a compatibility layer that allows calling them in the old location but that layer will be removed in 2.14.0.

Following the deprecation announcement for PostgreSQL 12 in TimescaleDB 2.10, PostgreSQL 12 is not supported starting with TimescaleDB 2.12. Currently supported PostgreSQL major versions are 13, 14 and 15. PostgreSQL 16 support will be added with a following TimescaleDB release.