Changelog

2022-05

This is a Long-Term Support release.

Upcoming Breaking Change

With the next release of IOWA, the configuration flags IOWA_SECURITY_LAYER_TINYDTLS, IOWA_SECURITY_LAYER_MBEDTLS, IOWA_SECURITY_LAYER_MBEDTLS_PSK_ONLY, IOWA_SECURITY_LAYER_MBEDTLS_OSCORE_ONLY will be deprecated. The configuration flag IOWA_SECURITY_LAYER_USER will be the default.

The samples secure_client_mbedtls3, secure_client_mbedtls2, and secure_client_tinydtls provides a feature equivalent integration with Mbed TLS and tinydtls. They also serve as a basis for integration with other TLS/DTLS libraries.

New Features

• It is now possible to set the access rights of a LwM2M Server to all known Objects at once by calling iowa_client_acl_rights_server_set() with IOWA_LWM2M_ID_ALL as the Object ID.
• Add a new API iowa_client_get_server_configuration() to retrieve a LwM2M Server setting.
• More LwM2M Server settings are accessible, including the CoAP retransmission parameters. See iowa_server_setting_id_t.
• IOWA generates new events of type IOWA_EVENT_SERVER_SETTING_CHANGED when a LwM2M Server setting is modified by a LwM2M operation on the LwM2M Server Object. See iowa_event_t.
• The provided implementations of the Location Object (ID: 6) and the IPSO Location Object (ID: 3336) have new APIs iowa_client_location_update_with_time(), iowa_client_location_update_full_with_time(), iowa_client_gps_update_location_with_time(), and iowa_client_gps_update_location_full_with_time() allowing the caller to specify the measurement timestamp.
• Add a new API `iowa_coap_peer_proxied_get() to perform a GET through a forward-proxy.

Breaking Change

• The value IOWA_IPSO_LEVEL_CONTROL is no longer part of the enumeration iowa_IPSO_ID_t. To manipulate an IPSO level sensor, please use the IPSO Dimmer Object APIs. Note that the IPSO Level Control Object was renamed "Dimmer" in the LwM2M Registry.

Behavior Changes

• When a Response is bigger than the connection MTU, and IOWA_COAP_BLOCK_SUPPORT is defined, IOWA will now return the first block of the response instead of returning a 4.13 (Request Entity Too Large) code.
• The iowa_server_info_t structure now contains the LwM2M protocol version used by the LwM2M Server.

SDK Changes

• Some internal functions were renamed to avoid conflicts.
• Add three new samples illustrating how to integrate with a DTLS/TLS security library, one using Mbed TLS 3.1, one using Mbed TLS 2.28, and one using tinydtls.
• The sample custom_object_multiple_instances, illustrating how to manage multiple instances of a custom LwM2M Object, was simplified and documented.

Bug Fixes

• Fix a bug where corrupted data retrieved from the notification storage queues may lead to out-of-range memory accesses or value underflows.
• Fix a bug where a Notification bigger than the connection MTU was not correctly sent as the first block of a CoAP Block-Transfer.
• Fix a potential crash when handling a Observation on a multiple resource with no instance in Clients with no support of the Observe-Composite operation.
• Fix a bug where IOWA was returning an error to the LwM2M Server cancelling the Firmware Update process. The Firmware Update process was however cancelled correctly.
• Fix a bug where a Server lifetime or binding modified by calling iowa_client_set_server_configuration() was not automatically saved when IOWA_STORAGE_CONTEXT_AUTOMATIC_BACKUP is defined.
• Fix a bug where the Access Control List Object Instances where not correctly restored when loading a context. The saved access control rights were however still enforced.