The experimental feature
indices.fielddata.cache.expire has been removed.
For indices that have this setting configured, this config will be ignored.
Previously, thread pool types could be dynamically adjusted. The thread pool type effectively
controls the backing queue for the thread pool and modifying this is an expert setting with minimal practical benefits
and high risk of being misused. The ability to change the thread pool type for any thread pool has been removed; do note
that it is still possible to adjust relevant thread pool parameters for each of the thread pools (e.g., depending on
the thread pool type,