v0.15.0

Highlights:

• Zephyr port updated to Zephyr v3.7
• NCS port updated to NCS v2.7
• ESP-IDF port updated to ESP-IDF v5.3

Added:

• native_sim platform support in Zephyr's twister execution of
  fw_update example

Changed:

• Use VERSION file to specify application version in fw_update
  example
• Better error message on manifest decode error
• Updated libcoap version to v4.3.4a
• Merged GOLIOTH_SAMPLE_{,PSK_}SETTINGS Kconfig settings
• Added extern "C" in headers for improved C++ compatibility

Fixed:

• CoAP keepalive behavior with Zephyr
• Memory leak by freeing post_block memory in purge_request_mbox()
• Disabled FreeRTOS logging backend on client disconnect
• Stop client during client destroy in golioth_client_destroy()

Known Issues:

• [Zephyr only] Espressif devices have a regression in Zephyr 3.7 that
  frequently causes crashes during flash operations. We recommend remaining
  on Zephyr 3.6 and Golioth Firmware SDK [0.14.0] until the issue is
  is resolved. For more information see
  zephyrproject-rtos/zephyr#77952
• [Zephyr only] Boards utilizing the ESP AT WiFi
  driver,
  such as the nRF52840 DK + ESP32, frequently fail to complete DTLS
  handshakes when using certificate authentication due to an issue with
  DTLS fragment handling when operating in passive mode, which is
  required for DNS resolution in Zephyr 3.7. For more information see
  zephyrproject-rtos/zephyr#77993

Workarounds:

• The MIMXRT1024-EVK received a new upstream Ethernet driver that was
  found to have sporadic "Link Down/Up" events that cause a loss of
  connectivity when downloading binaries during OTA Firmware Update. All
  Zephyr examples in this release include an overlay file for this board
  that reverts to the old driver.