The internal setting cluster.routing.allocation.snapshot.relocation_enabled that allowed shards with running snapshots to be reallocated to different nodes has been removed. Enabling this setting could cause allocation issues if a shard got allocated off a node and then reallocated back to this node while a snapshot was running.

Store throttling has been removed. As a consequence, the indices.store.throttle.type and indices.store.throttle.max_bytes_per_sec cluster settings and the index.store.throttle.type and index.store.throttle.max_bytes_per_sec index settings are not recognized anymore.

The default index.store.type has been removed. If you were using it, we advise that you simply remove it from your index settings and Elasticsearch will use the best store implementation for your operating system.