1# Change Log 2All notable changes to this project will be documented in this file. 3 4The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/) 5and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html). 6 7--- 8 9## [Unreleased] 10 11### Fixed 12### Added 13### Changed 14 15## Changes September 2020 16 17### Fixed 18 19### Added 20- `btstack_ring_buffer`: add `btstack_ring_buffer_reset` to reset it to initial state/empty 21- GAP: Support for address resolution of resolvable private addresses by Controller with `ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION` 22 23### Changed 24 25## Changes August 2020 26 27### Fixed 28- ESP32: fix authentication for incoming Secure Connections 29 30### Added 31- `btstack_run_loop_base`: added `btstack_run_loop_base_dump_timer` 32- GAP: request role change for classic connection via `gap_request_role` 33- GAP: LE Whitelist API with 'gap_le_whitelist_x' with x = add, remove, clear and new `gap_connect_with_whitelist` 34- SDP Client: add sdp_client_register_query_callback() allows to register query request instead of polling sdp_client_ready() 35- BNEP lwIP: add `bnep_lwip_connect` to establish BNEP connection and manage lwIP network interface 36- New `btstack_linked_queue` utility, a linked list-based queue with first-in-first-out semantics and constant time enqueue/dequeue operations 37 38### Changed 39- GAP: treat AES-CCM encrypted connection as mutually authenticated (BIAS) 40- GAP: 'gap_auto_connect_x' API deprecated. Please manage LE Whitelist and call `gap_connect_with_whitelist` instead 41 42## Changes July 2020 43 44### Fixed 45- AVDTP: fix invalid response for Get Capabilities request if Delay Reporting was supported 46- AVDTP: handle concurrent signaling establishment with reject and retry 47 48### Added 49- example/hid_host_demo: support reconnect from HID device 50- Crypto: support software AES128 for AES-CCM operations 51- AVRCP: introduced AVRCP_FEATURE_MASK_* as alternative to avrcp_controller_supported_feature_t and avrcp_target_supported_feature_t enums 52- btstack_audio: add set_volume() to sink and set_gain() to source interfaces, minimal volume control for portaudio playback 53- AVDTP: renamed definition of supported features from AVDTP_SOURCE_SF_ and AVDTP_SINK_SF_ to AVDTP_SOURCE_FEATURE_MASK_ and AVDTP_SINK_FEATURE_MASK_ respectively 54- GAP: Provide gap_get_role to query master/slave role for HCI connection handle 55- GAP: Provide gap_pin_code_response_binary to use binary data as PIN, e.g. for pairing with Nintendo Wii Remote 56 57### Changed 58- GAP: set minimum required encryption key size for Classic connections back from 16 to 7, matching the Core spec 59 60 61## Changes June 2020 62 63### Fixed 64- HFP: Fix parsing of empty fields, e.g. phone number in +CLCC and other AT commands 65- sm: Fix validation of confirm value for secure connection Passkey entry 66- AVRCP: handle concurrent signaling establishment with reject and retry 67 68### Added 69- GAP: Detect Secure Connection -> Legacy Connection Downgrade Attack by remote features and actual encryption type (BIAS) 70- GAP: Mutual authentication: request authentication after Classic connection got encrypted (BIAS) 71- Windows port for Dialog DA14585 connected via serial port 72 73## Changes 74- CVSD PLC: treat zero frames as good and allow to mark data as bad, e.g. if reported by Controller as erroneous 75 76## Changes May 2020 77 78### Fixed 79- hfp_hf, hsp_hs: use eSCO params in accept sco connection only for incoming eSCO connections 80- pbap_client: fix PBAP UUID len on connect message 81- sm: fix secure connection pairing as peripheral when local user confirmation happens after remote one 82- A2DP Source: only connect to remote sink stream endpoints 83- btstack_hal_flash_memory: fix write of 0xff bytes to simulated flash 84- hsp_hs: fix disconnect if audio not connected 85- hsp_ag: fix accept incoming connection 86 87### Added 88- example/le_mitm: MITM implementation that forwards ATT PDUs and allows for pairing 89- GAP: gap_set_security_level sets required security level for incoming and outgoing connections 90- cc256x: allow to specify power vector for each modulation type 91- FreeRTOS: btstack_run_loop_freertos_trigger_exit allows to request run loop exit 92- sm: support LE Secure Connections Only mode with sm_set_secure_connections_only_mode 93- GAP: enable BR/EDR Secure Connections if supported, add gap_secure_connections_enable 94 95### Changed 96- L2CAP ERTM: send extended features request only once per HCI connection 97 98 99## Changes April 2020 100 101### Fixed 102- hog_mouse_demo/hog_keyboard_demo: handle set protocol mode = boot protocol mode 103- HCI: only update BD_ADDR placeholder in shortened and complete name in EIR data, limit device name to 240/248 bytes 104 105### Added 106- GAP: gap_set_allow_role_switch allows to prevent role switch in outgoing classic ACL connections 107- example: hog_boot_host_demo implements an HID-over-GATT Boot Host that supports keyboard and mouse 108- HCI: add ENABLE_LE_LIMIT_ACL_FRAGMENT_BY_MAX_OCTETS that forces fragmentation of ACL-LE packets to fit into over-the-air packet 109 110### Changed 111- Broadcom/Cypress: wait 300 ms after PatchRAM update in hci.c to assert Controller is ready 112- esp32: provide esp-idf/component/btstack/btstack_port_esp32.c and only minimal app_main in template/main/main.c 113- att_db: skip att_read_callback for ATT Read Blob Request if offset == value_len 114 115 116## Changes March 2020 117 118### Fixed 119- GAP: fixed gap_set_scan_parameters() if issued right before gap_start_scan() 120- HCI: only send HCI Read Local Encryption Key Size if supported by Controller 121 122### Added 123- GATT Client: allow to register for any notification/indication and/or any connection 124- HCI: added hci_read_inquiry_scan_activity and hci_write_inquiry_scan_activity commands 125- chipset: assert hci packet buffers are suitable for firmware upload or patches (atwilc3000,bcm,cc256x,intel) 126- btstack_util: added btstack_replace_bd_addr_placeholder 127 128### Changed 129- AVRCP Target: volume in avrcp_target_volume_changed is reported as current value in interim response to register for volume change notifications 130- SDP Client: query attributes 0x0000..0xffff instead of 0x0001..0xffff to match other stacks / improve compatibility with bad sdp server implementations 131 132 133## Changes Februar 2020 134 135### Fixed 136- AVRCP Target: fix reporting of PLAYBACK_STATUS_CHANGED 137- HCI: handle reconnect request for Classic and LE connections triggered by packet handler for Disconnection Complete Event 138 139### Changed 140- hid_host_mode: allow sniff mode 141 142### Added 143- port/qt-usb and port/qt-h4: integrate BTstack Qt run loop for Unix- and Win32-based Qt application connected to Bluetooth module via H4 over serial port or USB 144 145 146## Changes January 2020 147 148### Fixed 149- L2CAP ERTM: avoid read-after-free on decline of incoming connection 150- GATT Client: set uuid16 to zero when deserializing uuid128 services, characteristics, and descriptors 151- att_db_util: fix realloc of att db buffer for large attributes 152- btstack_tlv_posix: only keep last value in memory, fix delete operation 153- l2cap_signaling: use packet boundary flags 0x00 for LE signaling packets (ignoring hci_non_flushable_packet_boundary_flag_supported()) 154 155### Added 156- att_db_util: provide GATT Database Hash via att_db_util_hash_calc 157- GATT Compiler: provide GATT Database Hash via GATT_DATABASE_HASH Characteristic 158- ATT Server: validate request pdu length 159 160### Changed 161- Crypto: update AES-CMAC implementation to access all message bytes sequentially 162 163 164## Changes December 2019 165 166### Fixed 167- example/pan_lwip_http_server: use Network Access Point, CoD 168- sm: emit pairing complete in master role when no keys are distributed / bonding disabled 169 170### Added 171 172### Changed 173- Updated CC256x initscript: CC256xC v1.3 174- ESP32: add CMake project files 175 176 177## Changes November 2019 178 179### Fixed 180- AVDTP Source: return correct `avdtp_cid` and `local_seid` in `AVDTP_SUBEVENT_STREAMING_CAN_SEND_MEDIA_PACKET_NOW` 181- L2CAP: send LE Data Channel SDUs round robin with other data 182- L2CAP ERTM: send ERTM I-frames round robin with other data 183 184### Added 185- ATT Server: return error if request to send now for Notification or Indication already registered 186- Linked List: return if item was added for `btstack_linked_list_add[_tail]` 187- btstack_run_loop_remove: return bool true if timer/data source was removed 188- segger-rtt: allow to configure with `SEGGER_RTT_PACKETLOG_*` directives, update to v6.54 189- GAP: support setting Link Supervision Timetout for outgoing Classic connections using `gap_set_link_supervision_timeout` 190- lwip: add download test files to http server demo 191 192### Changed 193- Linked List: return bool true if item was removed 194 195 196## Changes October 2019 197 198### Fixed 199 200### Added 201- `btstack_bool.h`: provide boolean type 'bool' via `<stdbool.h>` or as backport 202- provide `btstack_assert(condition)` 203- H4 Transport: avoid calling `hci_transport_h4_trigger_next_read` when transport is closed 204 205### Changed 206- libusb and posix ports: store bonding information in TLV 207 208 209## Changes September 2019 210 211### Fixed 212- L2CAP ERTM: assert that packet can be stored in fragment buffers in ertm 213- L2CAP ERTM: reject incoming connection if ERTM is configured as mandatory but not supported by remote 214- GATT Client: allow Write Without Response independent of other requests 215 216### Added 217- GAP: allow to reject GAP classic connection via gap_register_classic_connection_filter 218- GAP: support reading RSSI for Classic+LE using gap_read_rssi. Emits `GAP_EVENT_RSSI_MEASUREMENT` 219 220### Changed 221- Bluetooth and BTstack Error Codes and Events: collect status codes in bluetooth.h and events in btstack_defines.h 222- bluetooth.h: extract internal defintitions to respective protocol layers 223- Updated CC256x initscripts (CC256xB v1.8, CC256xC v1.2, CC256xC v1.2) 224 225 226## Changes August 2019 227 228### Fixed 229- POSIX, WICED, Windows, FreeRTOS run loops: handle time_ms overrun after 49 days 230- RFCOMM: accept incoming L2CAP connection in Basic mode if ERTM is enabled but not requested for this connection 231- RFCOMM: limit RFCOMM MTU by local L2CAP MTU for outgoing connections (only revelvant for ERTM) 232- L2CAP ERTM: stop timers on disconnect 233- L2CAP ERTM: fix sending of segmented SDUs 234- L2CAP ERTM: handle unsupported Information Response 235- SM: generate local nonce for confirm value in JW+NC+PK in Secure Connections Responder role 236 237### Added 238- `btstack_run_loop_base`: portable implementation of timer and data source management as base for platform specific implementations 239 240## Changed 241- FreeRTOS: use xQueueCreateStatic (static variant of xQueueCreate) if available for static memory-only setups 242- L2CAP ERTM: handle invalid Information Response (assume no extended features supported) 243- POSIX: use monotonic clock as timebase if available 244- HCI Transport H4/H5/EM9304 SPI: ignore block read/sent from UART driver when closed 245- HCI: Read Encryption Key Size after encryption was enabled 246- Errata 11838: 247 - GAP: gap_set_required_encryption_key_size allows to set the required key size, default = 16 (max) 248 - GAP: validate encryption key size to emit GAP Security Levels 249 250## Changes July 2019 251 252### Fixed 253- SM: Fixed regression introduced in f3582630 254- L2CAP: avoid reading l2cap signaling command len out of bounds 255- HCI Transport H4/H5/EM9304 SPI: fix payload size checks (also for 8/16-bit platforms) 256 257### Changed 258- SM: Start encryption upon receiving slave securiy request if bonded 259- hci: use 2 as HCI_INCOMING_PRE_BUFFER_SIZE in LE-only configuration for GATT Client 260 261--- 262 263## Changes June 2019 264 265### Changed 266- FreeRTOS: use freertos/.. prefix to include FreeRTOS headers if HAVE_FREERTOS_INCLUDE_PREFIX is defined 267- BNEP: add Connection Handle to BNEP_EVENT_CHANNEL_OPENED 268- Examples: renamed le_counter to gatt_counter and le_streamer to le_streamer_server to indicate suppport for GATT over BR/EDR 269 270### Fixed 271- BNEP: Bluetooth address is stored in little-endian format for all BNEP_EVENT_* 272- libusb: avoid use-after-free for SCO packets on disconnect 273 274### Added 275- example: pan_lwip_http_server using lwIP as network stack to implement PAN NAP service 276- platform/lwip/bnep_lwip.c: BNEP lwIP adapter that forwards packets between BNEP service and lwIP 277- ENABLE_GATT_OVER_CLASSIC enables support for GATT over BR/EDR in att_server 278 279--- 280 281## Changes May 2019 282 283### Changed 284- ESP32: Configure SCO over HCI after power up 285- btstack_tlv_flash_bank: support targets where a value cannot be overwritten with zero. When ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 286 is defined, an explicit delete field is used to indicate an invalid entry. 287 288### Fixed 289- SM: Avoid potential use-after-free on immediate disconnect (lookup connection via con handle instead of storing pointer) 290 291### Added 292- gatt_client: emit query complete event for signed write operation 293- hci_transport_h4: add workaround for flow control bug in CYW2070x, enable with ENABLE_CYPRESS_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND 294 295--- 296 297## Changes April 2019 298 299### Changed 300- ESP32: use micro-ecc from 3rd-party as esp-idf removed it in their 3.3 release 301 302### Fixed 303- hci: pad LE Scan response with zeroes 304- SM: store local CSRK 305- ATT DB: call write callback for validated signed writes 306- ATT Server: abort signed write validation on incoming new request 307- Bluetooth SIG web scraping tools updated 308- libusb: compiles for FreeBSD 309 310### Added 311 312--- 313 314## Changes March 2019 315 316### Changed 317- use Makefile for stm32-f4discovery-cc256x port 318- le_device_db: add secure_connection argument to le_device_db_encryption_set and le_device_db_encryption_get 319 320### Fixed 321- SM: Use provided authentication requirements in slave security request 322 323### Added 324- port/stm32-f4discovery-cc256x: add support for built-in MEMS microphone 325- SM: Track if connection encryption is based on LE Secure Connection pairing 326- ATT DB: Validate if connection encrypted is based on SC if requested 327- att_db_util: support ATT_SECURITY_AUTHENTICATED_SC permission flag 328- GATT Compiler: support READ_AUTHENTICATED and WRITE_AUTHENTICATED permsission flags 329- ESP32: erase nvs flash is newer nvs version found 330- libusb: add support for nRF52840-PCA10056 running Zephyr hci_usb example 331- port/stm32-l073rz-nucleo-em9304 for Nucleo L073RZ with EM9304 DVK, replaces port/stm32-l053r8-nucleo-em9304 332 333## Changes February 2019 334 335### Changed 336- example/a2dp_sink_demo: use linear resampling to fix sample rate drift 337- btstack_audio: split interface into sink and source 338 339### Fixed 340- Crypto: fix lockup when stack is shutdown while waiting for result of HCI Command, e.g. LE Read Local P256 Public Key 341- SM: Avoid SM_EVENT_PAIRING_COMPLETE with ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION after successful pairing in responder role 342 343### Added 344- example/a2dp_sink_demo: add target role, support volume control on both devices 345- example/audio_duplex: playback audio audio source on audio sink (test audio path) 346- btstack_audio_embedded: implement audio source path 347 348--- 349 350## Changes January 2019 351 352### Changed 353- L2CAP: provide channel mode (basic/ertm) and fcs option in L2CAP_EVENT_CHANNEL_OPENED 354- RFCOMM: support L2CAP ERTM. Callbacks passed to rfcomm_enable_l2cap_ertm() are used to manage ERTM buffers 355 356### Added 357- L2CAP: emit L2CAP_EVENT_ERTM_BUFFER_RELEASED if ERTM buffer not needed/used anymore 358- L2CAP: add fcs_option to ERTM config l2cap_ertm_config_t 359- HCI: validate advertisement data length field when generating GAP_EVENT_ADVERTISING_REPORT 360- ad_parser: validate data element length fields in ad_iterator_has_more 361- Raspberry Pi 3 A+/B+ port in port/raspi, starts without power cycle 362 363### Fixed 364- HCI: release outgoing buffer on disconnect if waiting to send another ACL fragment 365- POSIX: use correct baudrate enums for baud rates higher than 921600 (Linux) 366- Crypto: directly process queued crypto operation on HCI result 367 368--- 369 370## Changes December 2018 371 372### Added 373- SM: generate and store ER / IR keys in TLV, unless manually set by application 374- hci_dump: support PacketLogger or BlueZ format output via SEGGER RTT Channel 1 Up 375 376### Fixed 377- SM: fix internal buffer overrun during random address generation 378 379## Changes November 2018 380 381### Added 382- GAP: gap_le_connection_interval provides connection interval for conn handle 383- Nordic SPP Service Server: GATT service that emulates a serial port over BLE based on Nordic Semiconductor documentation. 384- uBlox SPP Service Server: GATT service that emulates a serial port over BLE based on uBlox documentation. 385- SM: ENABLE_LE_CENTRAL_AUTO_ENCRYPTION triggers automatic encryption on connect to bonded devices 386- SM: generate and store ER / IR keys in TLV, unless manually set by application 387 388### Fixed 389- SM: prevent random address updates if gap_random_address_set was used 390- SM: fix internal buffer overrun that can cause storing of bonding information to fail 391- SM: ignore Slave Security Request after sending own Pairing Request 392- L2CAP: fix use after free on disconnect if ERTM is enabled 393- HFP: Handle multiple commands/responses in single RFCOMM packet 394- Memory Pools: clear all buffers before use 395 396--- 397 398## Changes October 2018 399 400### Added 401- SDP Server: queue incoming connections when already connected instead of rejecting them 402- GAP: Support enter/exit sniff mode via gap_sniff_mode_enter/exit. gap_set_default_link_policy_settings is needed to enable sniff mode in general. 403- HIDS Device: GATT service that exposes HID reports intended for HID Devices, like keyboard and mouse. 404 405### Fixed 406- HCI: fix bug in gap_inquiry_stop that triggered additional GAP_EVENT_INQUIRY_COMPLETE instead of stopping the inquiry 407- L2CAP: fix issue with outgoing connection before read remote supported complete when other channels exist 408- L2CAP ERTM: allow SDU of szie MPS in first packet that contains L2CAP SDU Length 409- L2CAP ERTM: fix memory corruption triggered if local_mtu > mps 410- L2CAP ERTM: fix outgoing fragment management 411- HFP: decline incoming RFCOMM connection after outgoing connection was started 412- AVRCP: fix crash on disconnect of connection established by remote 413 414--- 415 416## Changes September 2018 417 418### Fixed 419- HCI: Error creating outgoing connection (e.g. Connection Limit Exceeded) now handled 420- L2CAP: Error creating outgoing connection (e.g. Connection Limit Exceeded) now handled 421- L2CAP: Evaluate 'can send now' on HCI Disconnect as ACL buffers in Bluetooth Controller have been used for the closed connection are freed implicitly 422- L2CAP: Check can send now before sending extended information requeste needed for ERTM mode 423- L2CAP: Use valid signaling identifier for L2CAP Connection Parameter Update Request 424- RFCOMM: Trigger l2cap request to send on rfcomm credits when client is waiting to sendtrigger l2cap request to send on rfcomm credits when client is waiting to send 425- RFCOMM: Avoid use-after-free on channel finalize 426- GATT Client: stop timer on disconnect - fixes use after free / crash 427 428### Added 429- A2DP Source: Support stream reconfiguration (a2dp_source_reconfigure_stream_sampling_frequency) 430- 3rd-party: yxml is used for PBAP vCard list parsing 431- cc256xC: new v1.1 init scripts 432 433--- 434 435## Changes August 2018 436 437### Added 438- PBAP: added pbap_get_phonebook_size() to get phonebook entry count 439 440### Fixed 441- GATT Server: Allow enable Notifications/Indication with Write Command. Fixes issue with some Android devices. 442- SM: fix pairing for Secure Connections with Bonding if remote sends additional keys 443- SM: drop LTK flag from Pairing Response for Secure Connections 444- L2CAP: fix emitted L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_REQUEST 445 446## Changes June 2018 447 448### Added 449- btstack_audio.h: application level API for audio playback and recording 450- embedded/hal_audio.h: low-level API for audio playback and recording 451- HID Device: hid_device_connect(..) function 452- ESP32: implement hal_audio 453- DA14585: support for Dialog Semiconductor DA14585 LE-only controller 454- Raspberry Pi 3 + Raspberry Pi Zero W port in port/raspi 455 456### Changed 457- Errata 10734: 458 - SM: Generate new EC Public Keypair after each pairing 459 - SM: Abort failure with DHKEY_CHECK_FAILED if received public key is invalid (instead of unspecified error) 460- btstack.h: only include classic headers if ENABLE_CLASSIC is defined 461- windows: ignore virtual Bluetooth adapter provided by VMware 462- Replaced HCI_PACKET_BUFFER_SIZE with HCI_INCOMING_PACKET_BUFFER_SIZE and HCI_OUTGOING_PACKET_BUFFER_SIZE 463 464--- 465 466## Changes June 2018 467 468### Fixed 469- HFP: Fix Wide Band Speech bit in SDP record for both HF/AG. Missing bit prevents macOS from using mSBC 470- ATT Server: send ATT_EVENT_HANDLE_VALUE_INDICATION_COMPLETE with status ATT_HANDLE_VALUE_INDICATION_DISCONNECT on disconnect 471- AVRCP Controller: fix parsing of now playing info 472 473### Changed 474- ATT Server: ATT_HANDLE_VALUE_INDICATION_DISCONNECT is delivered to service handler if registered 475 476### Added 477- ATT Server: packet handler field added to att_service_handler_t to receive: connect/disconnect, atu exchange, indication complete 478 479--- 480 481## Changes May 2018 482 483### Added 484- GAP: re-encrypt outgoing connection if bonded 485- ATT Server: wait until re-encryption is complete 486- GATT Client: wait until re-encryption is complete 487- ATT Server: added att_server_request_to_send_notification and att_server_request_to_send_indication 488- GATT Client: if ENABLE_GATT_CLIENT_PAIRING, GATT Client starts pairing and retry operation on security error 489 490### Changed 491- ATT Server: att_server_register_can_send_now_callback is deprecated, use att_server_request_to_send_notification/indication instead 492 493### Fixed 494- SM: Fix LE Secure Connection pairing in Central role 495- le_device_db_tlv: fix seq nr management 496- SM: improve le_device_db lookup and storing of IRK 497- GATT Server: fix lookup for Client Characteristic Configuration in services with multiple Characteristics 498- RFCOMM: emit channel closed on HCI/L2CAP disconnect after sending DISC while expecting UA 499 500--- 501 502## Changes April 2018 503 504### Added 505- Crypto: btstack_crypo.h provides cryptographic functions for random data generation, AES128, EEC, CBC-MAC (Mesh) 506- SM: support pairing using Out-of-Band (OOB) data with LE Secure Connections 507- Embedded: support btstack_stdin via SEGGER RTT 508 509### Changed 510- att_db_util: added security requirement arguments to characteristic creators 511- SM: use btstack_crypto for cryptographpic functions 512- GAP: security level for Classic protocols (asides SDP) raised to 2 (encryption) 513 514### Fixed 515- HFP: fix answer call command 516- HCI: fix buffer overrun in gap_inquiry_explode 517- SDP: free service record item on sdp_unregister_service 518 519## Changes March 2018 520 521### Added 522- GAP: allow to limit number of connections in LE Peripheral role with gap_set_max_number_peripheral_connections 523- ATT Server: support for delayed ATT read response, see example/att_delayed_read_response.c 524- ATT Server: allow to specify security requirements seperately for read/writes. .h files need to be regenerated 525 526### Fixed 527- RFCOMM: fix infinite loop on L2CAP connection error (regression from 4c3eeed1) 528- HSP HS: accept incomming SCO connection 529- SM: fix iteration over LE Device DB entries for bonding and address resolving 530- SM: store pairing information only if both devices have requested bonding 531 532--- 533 534## Changes February 2018 535 536### Added 537- GATT Client: gatt_client_request_can_write_without_response_event() causes GATT_EVENT_CAN_WRITE_WITHOUT_RESPONSE 538- SM: new event SM_EVENT_PAIRING_COMPLETE 539- GAP: support iteration over stored Classic link keys: gap_link_key_iterator_init, gap_link_key_iterator_get_next, gap_link_key_iterator_done 540- GAP: add gap_delete_all_link_keys 541 542### Changed 543- GATT Client: round robin for multiple connections 544- ATT Dispatch: round robin for ATT Server & GATT Client 545- L2CAP: round robin for all L2CAP channels (fixed and dynamic) 546- btstack_link_key_db: addition functions for link key iteration 547- GAP: LE scanning enabled not reset on HCI Reset -> can be enabled before HCI Power Up 548- CSR: set all keys in psram instead of default 549 550### Fixed 551- tc3556x: fix startup after baud rate change 552 553--- 554 555## Changes January 2018 556 557### Added 558- Port for Windows with Zephyr HCI Firmware connected via serial port 559- em9304: upload patch containers during HCI bootup 560- Makefile for STM32-F4Discovery port 561- support for console out via SEGGER RTT 562- LE Data Channels example in BTstack and [iOS example on GitHub](https://github.com/bluekitchen/CBL2CAPChannel-Demo) 563- LE Streamer Client can send as fast as possbile as well 564- L2CAP: option to limit ATT MTU via l2cap_set_max_le_mtu 565 566### Changed 567- HCI: allow to set hci_set_master_slave_policy (0: try to become master, 1: accept slave) 568- GAP: gap_set_connection_parameters includes scan interval and window params 569- GATT Client: GATT_EVENT_MTU indicates max MTU 570- ATT DB Util: attribute handle is returned for new Services and Characteristics 571 572### Fixed 573- Windows: retry serial port operations if not all bytes have been read/written 574- HFP: avoid buffer overflows setting up messages 575- SBC Decoder: improved error handling for invalid SBC audio data 576- GAP: fix Connection Parameter Response in Central role 577- ATT DB Util: update pointer to database in case of realloc 578- GATT Client: set UUID16 field if 16-bit UUID is stored as UUID128 579- GAP: release HCI Connnection after gap_le_conne 580- ATT: Exchanged MTU is propagate to ATT Server and GATT Client 581 582--- 583 584## Changes December 2017 585 586### Added 587- Introduced btstack_network.h network interface abstraction 588- btstack_network_posix implementation using Linux tun/tap interface 589- WICED: support for btstack_stdin (HAVE_STDIN) 590- GATT Server: Writes to GATT Client Characteristic Configuration are stored in TLV and restored on reconnect. The db.h file generated from db.gatt needs to be re-created. 591- TLV: global TLV instance available via btstack_tlv_get_instance() (src/btstack_tlv.h) 592- TLV: POSIX implementation that appends to a file on disk (platform/posix/btstack_tlv_posix.c 593- LE Device DB TLV: overwrite oldest entry if no free entries available 594- SM: allow to set fixed passkey in display role using sm_use_fixed_passkey_in_display_role 595- Example/hid_host_demo with HID parser and support for basic US keyboard layout 596- EM9304: custom HCI Transport implementation for EM9304 on top of btstack_em9304_spi.h platform abstraction only requires hal_em9304_spi.h to be implemented for new ports 597- Port for Apollo2 MCU with EM9304 (ports/apollo2-em9304) 598 599### Changed 600- panu_demo: uses btstack_network.h now 601- WICED: configure printf to replace Linefeed with CRLF 602- SBC: split btstack_sbc_bludroid.c into seperate encoder and decoder implementations 603 604### Fixed 605- RFCOMM: support connection requests during connection failure 606- L2CAP: support connection requests during connection failure 607- L2CAP: fix default remote MTU as 672 instead of 48 (Minimal MTU) 608- HCI: avoid double free during halting 609- SM: fixed reconnect using legacy pairing in slave role 610 611 612