Built with the APPLICATION_EXTENSION_API_ONLY setting enabled.

Fixed a bug that could have caused the client to not reissue the active subscriptions on the next connection attempts when the device switched several times between online and offline mode.

Discontinued a notification to the Server of the termination of a HTTP streaming session. The notification could help the Server to detect closed connections in some cases, but in other cases it could give rise to bursts of new connections.

The library is now built and distributed as an XCFramework.

Introduced support for running watchOS Simulator on Apple Silicon Macs.

Dropped distribution via CocoaPods, replaced with Swift Package Manager.

Revised the policy of reconnection attempts to reduce the attempt frequency in case of repeated failure of the first bind request, which could be due to issues in accessing the "control link" (when configured).

Updated documentation of LSMPNDevice and event mpnDeviceDidResume: of LSMPNDeviceDelegate to reflect changes on Server version 7.1. In particular, a suspended MPN device now is resumed at the first subsequent registration (a token change is no more required). COMPATIBILITY NOTE: If upgrading the SDK and keeping Server version 7.0, some parts of the documentation will become slightly incorrect, but the application will work exactly as before. Note: this documentation change was already included by mistake since version 4.1.0 of this SDK.

Fixed a bug causing sessionId of LSConnectionDetails to return nil notwithstanding the connection status was CONNECTED:STREAM-SENSING.

Fixed a bug affecting the various callbacks that report custom error codes and error messages received from Lightstreamer Server (originated by the Metadata Adapter). The message reported could have been in a percent-encoded form.

By-passed the retryDelay setting when recovering from a closed session. This may speedup the recovery process.

Clarified in the docs the role of delayTimeout in sendMessage:withSequence:timeout:delegate:enqueueWhileDisconnected.
Fixed typos in the docs of MPN-related methods.

Fixed a bug which caused an exception when the Server sent an invalid item name in two-level subscriptions instead of triggering the listener subscription:didFailWithErrorCode:message:forCommandSecondLevelItemWithKey: of LSSubscriptionDelegate with the error code 14 (Invalid second-level item name).

Fixed a bug affecting polling sessions, which, upon a connection issue, could have caused the session to be interrupted by issuing client:didReceiveServerError:withMessage:, instead of being automatically recovered.

Incremented the minor version number. COMPATIBILITY NOTE: If running Lightstreamer Server with a license of "file" type which enables watchOS Client SDK up to version 4.1 or earlier, clients based on this new version will not be accepted by the Server: a license upgrade will be needed.

Fixed race condition that under rare circumstances could have caused a crash when closing a connection that was actively receiving data.

Fixed a bug in the recently revised policy of reconnection attempts upon failed or unresponsive requests. In case of multiple failed attempts on unresponsive connections the retry delay was increased dynamically, but was not restored to the configured value after a successful connection. As a consequence, after a server or network unavailability lasting for a couple of minutes, further cases of server or network unavailability would be recovered in about one minute, even if much shorter.

Wholly revised the policy of reconnection attempts upon failed or unresponsive requests. Now the only property related with this policy is retryDelay, which now affects both (1) the minimum time to wait before trying a new connection to the Server in case the previous one failed for any reason and (2) the maximum time to wait for a response to a request before dropping the connection and trying with a different approach.
Previously, point (2) was related with the connectTimeout and currentConnectTimeout properties. Now, in case of multiple failed attempts on unresponsive connections (i.e. while in CONNECTING state), the timeout used may still be increased dynamically and can be inspected through currentConnectTimeout, but this behavior is no longer configurable. COMPATIBILITY NOTE: Existing code that tries to take control of the connection timeouts will no longer be obeyed, but we assume that the new policy will bring an overall improvement. Note that, when in CONNECTING state, the current timeout can be restored by issuing disconnect> and then connect. As a result of the change, properties connectTimeout and currentConnectTimeout of LSConnectionOptions have been deprecated, as the setters have no effect and the getter is now equivalent to retryDelay.
Also changed the default value of the retryDelay property from 2 seconds to 4 seconds.

Modified the implementation of connect when issued while the state is either DISCONNECTED:WILL-RETRY or DISCONNECTED:TRYING-RECOVERY. The call will no longer interrupt the pending reconnection attempt, but it will be ignored, to lean on the current attempt. Note that a pending reconnection attempt can still be interrupted by issuing disconnect first.
Modified in a similar way the implementation of forcedTransport property when issued while the state is either DISCONNECTED:WILL-RETRY or DISCONNECTED:TRYING-RECOVERY, the call will no longer interrupt the pending reconnection attempt, but it will apply to the outcome of that connection attempt.

Fixed a bug triggered by a call to connect or a change to forcedTransport issued while the Client was attempting the recovery of the current session. This caused the recovery to fail, but, then, the library might not reissue the current subscriptions on the newly created session.

Fixed a bug that could have caused session recovery to fail if preceded by a previous successful session recovery on the same session by more than a few seconds.

Changed the default value of the earlyWSOpenEnabled property from YES to NO.

Changed the default value of the slowingEnabled property from YES to NO.

Incremented the minor version number. COMPATIBILITY NOTE: If running Lightstreamer Server with a license of "file" type which enables watchOS Client SDK up to version 4.0 or earlier, clients based on this new version will not be accepted by the Server: a license upgrade will be needed.

Fixed a race condition that could lead the Client to stop trying to reconnect to the Server after a network disconnection or a server restart. This bug has been reported only when running on the Simulator, but could happen also on the device.

Added ARM64_32 code segments to the library binaries for compatibility with the latest Apple Watch architecture.

Fixed a bug causing a fatal error when the Client recreated a session because of a network error and there were active MPN subscriptions.

Fixed a bug causing the Client to ignore the sessionRecoveryTimeout when in state STALLED.

Fixed a bug causing the closing of the session when the user made a copy of a triggered LSMPNSubscription (with the copy constructor initWithMPNSubscription:) and then subscribed the copy.

Fixed reference cycles that could lead to memory leaks while trying to connect for extended periods of time or, once connected, when subscribing and unsubscribing multiple times.

Introduced a maximum time on attempts to recover the current session, after which a new session will be opened. The default is 15 seconds, but it can be customized with the newly added sessionRecoveryTimeout property in LSConnectionOptions. This fixes a potential case of permanently unsuccessful recovery, if the <control_link_address> setting were leveraged in a Server cluster and a Server instance happened to leave a cluster and were not automatically restarted.

Fixed a bug in the recently introduced session recovery mechanism triggered by the use of the <control_link_address> setting on Lightstreamer Server, which could have caused feasible recovery attempts to fail.

Fixed a bug in the recently introduced session recovery mechanism, by which, a "sendMessage" request issued while a recovery operation was in place, could have never been notified to the listener until the end of the session (at which point an "abort" notification would have been issued to the listener), even in case the recovery was successful.

Minor performance improvement in native HTTP connection mechanism by replacing threads with GCD queues

Added the error code 21 in client:didReceiveServerError:withMessage:, that can be received upon some failed requests, to inform that not only the current session was not found but it is also likely that the request was routed to the wrong Server instance. Previously, in the same cases, the SDK library would not invoke client:didReceiveServerError:withMessage: and would open a new session instead. COMPATIBILITY NOTE: If using an existing application, you should check how it would handle the new (and unexpected) error code. A reconnection attempt would ensure the previous behavior, although this is no longer the suggested action.

Modified the default value of the retryDelay property from 5 to 2 seconds. This should help recovering from network outages of a few seconds, typical, for instance, of wifi/mobile network switches.

Extended the recovery mechanism to stalled sessions. Now, when the reconnectTimeout expires, an attempt to recover the current session will be performed first.

Fixed a bug which could have caused the property snapshot of LSItemUpdate to behave wrongly on subscriptions in which the snapshot was not requested.

Fixed a bug preventing the connection when the Server configuration specifies a control-link address.

Fixed a bug which, in a slow client scenario, could have caused the interruption of a polling session due to a wrong request to the Server.

Fixed a race condition, mostly possible in an overloaded client scenario, which could have caused subscription or sendMessage requests to be delayed.

Fixed a harmless bug in the reverse heartbeat mechanism which, upon session startup, could have caused an exception to be logged on the console.

Fixed the instructions provided in the documentation of notificationFormat property of the LSMPNSubscription class.

Extended the scope of error code 41 on the various MPN requests to all issues related with resource unavailability in the Server preventing the operation. Previously, such issues could have caused the whole session to be interrupted.

Added clarifications on licensing matters in the docs.

Derived from iOS Client SDK 4.0.0 build 66.
Some features are missing. See the introduction of the API documentation for details.