min_version in the leafnodes{} that would reject servers with a lower version. Note that this would work only for servers that are v2.8.0 and above./healthz endpoint when failure occurs./varz endpoint.healthz endpoint.MaxAckPending value.unique_tag option in jetstream{} configuration block to prevent placing a stream in the same availability zone twice.Alternates field in StreamInfo response. They provide a priority list of mirrors and the source in relation to where the request originated.max_connections, max_subscriptions, max_payload, max_leafnodes) in server configuration file.MaxRequestBatch to limit the batch size any client can request MaxRequestExpires to limit the expiration any client can requestInactiveThreshold duration that instructs the server to cleanup ephemeral consumers that are inactive for that long.max_file_store and max_memory_store in the jetstream{} block as strings with the following suffixes K, M, G and T, for instance: max_file_store: "256M".MaxBytesRequired, which defines a per-account maximum bytes for assets./mqtt to the URL path.connection_rate_limit: <number of connections per seconds> in the tls{} top-level block./jsz and /varz endpointsMQTTClient in the /connz connections report and system events CONNECT and DISCONNECT. Ability to select on mqtt_client.$MQTT_sess_<xxxx> streams to a new $MQTT_sess stream for the user's account.PushBound in the consumer information object set by the server), this misbehavior is still possible.DeliverGroup in the consumer configuration, which won’t be set for existing JetStream consumers and by the older libraries, and detects interest (and starts delivering) only when a subscription on the deliver subject for a queue subscription matching the “deliver group” name is found. Since the JetStream consumer is thought to be a non-deliver-group consumer, the opposite happens: the server detects a core NATS queue subscription on the “deliver subject”, therefore does not trigger delivery on the JetStream consumer’s “deliver subject”.PushBound boolean set by the server, therefore will not be able to alert the user that they are trying to create multiple subscription instances for the same JetStream consumer.DeliverGroup field. The error will be likely to the effect that the user tries to create a queue subscription to a non-queue JetStream consumer. Note that if the application creates a queue subscription for a non-yet created JetStream consumer, then this call will succeed, however, adding new members or restarting the application with the now existing JetStream consumer will fail.DeliverGroup field will be set by the library or need to be provided when creating the consumer externally.DeliverGroup, so none of them can be used for queue subscriptions. They will have to be recreated.PubAck protocolPushBound boolean in ConsumerInfo to indicate that a push consumer is already bound to an active subscriptionDeliverGroup string in ConsumerConfig to specify which deliver group (or queue group name) the consumer is created forconnz informationresolver_pinned_accounts to ensure users are signed by certain accounts$SYS.REQ.SERVER.<id>.<endpoint-name> (request server monitoring endpoint corresponding to endpoint name.)$SYS.REQ.SERVER.PING.<endpoint-name> (from all server request server monitoring endpoint corresponding to endpoint name - will return multiple messages)no_auth_user Configurationno_auth_user allows you to refer to a configured user/account when no credentials are provided./routez and /connz. For instance /connz?subs=detail will now return not only the subjects of the subscription, but the queue name (if applicable) and some other details.logfile_size_limit allowing auto-rotation of log files when the size is greater than the configured limit set in logfile_size_limit as a number of bytes. You can provide the size with units, such as MB, GB, etc. The backup files will have the same name as the original log file with the suffix .yyyy.mm.dd.hh.mm.ss.micros. For more information see Configuring Logging in the NATS Server Configuration section.