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- HFP: fix parsing of ranges e.g. in +CIND responses 19 20### Added 21- `btstack_ring_buffer`: add `btstack_ring_buffer_reset` to reset it to initial state/empty 22- GAP: Support for address resolution of resolvable private addresses by Controller with `ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION` 23 24### Changed 25 26## Changes August 2020 27 28### Fixed 29- ESP32: fix authentication for incoming Secure Connections 30 31### Added 32- `btstack_run_loop_base`: added `btstack_run_loop_base_dump_timer` 33- GAP: request role change for classic connection via `gap_request_role` 34- GAP: LE Whitelist API with 'gap_le_whitelist_x' with x = add, remove, clear and new `gap_connect_with_whitelist` 35- SDP Client: add sdp_client_register_query_callback() allows to register query request instead of polling sdp_client_ready() 36- BNEP lwIP: add `bnep_lwip_connect` to establish BNEP connection and manage lwIP network interface 37- New `btstack_linked_queue` utility, a linked list-based queue with first-in-first-out semantics and constant time enqueue/dequeue operations 38 39### Changed 40- GAP: treat AES-CCM encrypted connection as mutually authenticated (BIAS) 41- GAP: 'gap_auto_connect_x' API deprecated. Please manage LE Whitelist and call `gap_connect_with_whitelist` instead 42 43## Changes July 2020 44 45### Fixed 46- AVDTP: fix invalid response for Get Capabilities request if Delay Reporting was supported 47- AVDTP: handle concurrent signaling establishment with reject and retry 48 49### Added 50- example/hid_host_demo: support reconnect from HID device 51- Crypto: support software AES128 for AES-CCM operations 52- AVRCP: introduced AVRCP_FEATURE_MASK_* as alternative to avrcp_controller_supported_feature_t and avrcp_target_supported_feature_t enums 53- btstack_audio: add set_volume() to sink and set_gain() to source interfaces, minimal volume control for portaudio playback 54- 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 55- GAP: Provide gap_get_role to query master/slave role for HCI connection handle 56- GAP: Provide gap_pin_code_response_binary to use binary data as PIN, e.g. for pairing with Nintendo Wii Remote 57 58### Changed 59- GAP: set minimum required encryption key size for Classic connections back from 16 to 7, matching the Core spec 60 61 62## Changes June 2020 63 64### Fixed 65- HFP: Fix parsing of empty fields, e.g. phone number in +CLCC and other AT commands 66- sm: Fix validation of confirm value for secure connection Passkey entry 67- AVRCP: handle concurrent signaling establishment with reject and retry 68 69### Added 70- GAP: Detect Secure Connection -> Legacy Connection Downgrade Attack by remote features and actual encryption type (BIAS) 71- GAP: Mutual authentication: request authentication after Classic connection got encrypted (BIAS) 72- Windows port for Dialog DA14585 connected via serial port 73 74## Changes 75- CVSD PLC: treat zero frames as good and allow to mark data as bad, e.g. if reported by Controller as erroneous 76 77## Changes May 2020 78 79### Fixed 80- hfp_hf, hsp_hs: use eSCO params in accept sco connection only for incoming eSCO connections 81- pbap_client: fix PBAP UUID len on connect message 82- sm: fix secure connection pairing as peripheral when local user confirmation happens after remote one 83- A2DP Source: only connect to remote sink stream endpoints 84- btstack_hal_flash_memory: fix write of 0xff bytes to simulated flash 85- hsp_hs: fix disconnect if audio not connected 86- hsp_ag: fix accept incoming connection 87 88### Added 89- example/le_mitm: MITM implementation that forwards ATT PDUs and allows for pairing 90- GAP: gap_set_security_level sets required security level for incoming and outgoing connections 91- cc256x: allow to specify power vector for each modulation type 92- FreeRTOS: btstack_run_loop_freertos_trigger_exit allows to request run loop exit 93- sm: support LE Secure Connections Only mode with sm_set_secure_connections_only_mode 94- GAP: enable BR/EDR Secure Connections if supported, add gap_secure_connections_enable 95 96### Changed 97- L2CAP ERTM: send extended features request only once per HCI connection 98 99 100## Changes April 2020 101 102### Fixed 103- hog_mouse_demo/hog_keyboard_demo: handle set protocol mode = boot protocol mode 104- HCI: only update BD_ADDR placeholder in shortened and complete name in EIR data, limit device name to 240/248 bytes 105 106### Added 107- GAP: gap_set_allow_role_switch allows to prevent role switch in outgoing classic ACL connections 108- example: hog_boot_host_demo implements an HID-over-GATT Boot Host that supports keyboard and mouse 109- HCI: add ENABLE_LE_LIMIT_ACL_FRAGMENT_BY_MAX_OCTETS that forces fragmentation of ACL-LE packets to fit into over-the-air packet 110 111### Changed 112- Broadcom/Cypress: wait 300 ms after PatchRAM update in hci.c to assert Controller is ready 113- esp32: provide esp-idf/component/btstack/btstack_port_esp32.c and only minimal app_main in template/main/main.c 114- att_db: skip att_read_callback for ATT Read Blob Request if offset == value_len 115 116 117## Changes March 2020 118 119### Fixed 120- GAP: fixed gap_set_scan_parameters() if issued right before gap_start_scan() 121- HCI: only send HCI Read Local Encryption Key Size if supported by Controller 122 123### Added 124- GATT Client: allow to register for any notification/indication and/or any connection 125- HCI: added hci_read_inquiry_scan_activity and hci_write_inquiry_scan_activity commands 126- chipset: assert hci packet buffers are suitable for firmware upload or patches (atwilc3000,bcm,cc256x,intel) 127- btstack_util: added btstack_replace_bd_addr_placeholder 128 129### Changed 130- AVRCP Target: volume in avrcp_target_volume_changed is reported as current value in interim response to register for volume change notifications 131- SDP Client: query attributes 0x0000..0xffff instead of 0x0001..0xffff to match other stacks / improve compatibility with bad sdp server implementations 132 133 134## Changes Februar 2020 135 136### Fixed 137- AVRCP Target: fix reporting of PLAYBACK_STATUS_CHANGED 138- HCI: handle reconnect request for Classic and LE connections triggered by packet handler for Disconnection Complete Event 139 140### Changed 141- hid_host_mode: allow sniff mode 142 143### Added 144- 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 145 146 147## Changes January 2020 148 149### Fixed 150- L2CAP ERTM: avoid read-after-free on decline of incoming connection 151- GATT Client: set uuid16 to zero when deserializing uuid128 services, characteristics, and descriptors 152- att_db_util: fix realloc of att db buffer for large attributes 153- btstack_tlv_posix: only keep last value in memory, fix delete operation 154- l2cap_signaling: use packet boundary flags 0x00 for LE signaling packets (ignoring hci_non_flushable_packet_boundary_flag_supported()) 155 156### Added 157- att_db_util: provide GATT Database Hash via att_db_util_hash_calc 158- GATT Compiler: provide GATT Database Hash via GATT_DATABASE_HASH Characteristic 159- ATT Server: validate request pdu length 160 161### Changed 162- Crypto: update AES-CMAC implementation to access all message bytes sequentially 163 164 165## Changes December 2019 166 167### Fixed 168- example/pan_lwip_http_server: use Network Access Point, CoD 169- sm: emit pairing complete in master role when no keys are distributed / bonding disabled 170 171### Added 172 173### Changed 174- Updated CC256x initscript: CC256xC v1.3 175- ESP32: add CMake project files 176 177 178## Changes November 2019 179 180### Fixed 181- AVDTP Source: return correct `avdtp_cid` and `local_seid` in `AVDTP_SUBEVENT_STREAMING_CAN_SEND_MEDIA_PACKET_NOW` 182- L2CAP: send LE Data Channel SDUs round robin with other data 183- L2CAP ERTM: send ERTM I-frames round robin with other data 184 185### Added 186- ATT Server: return error if request to send now for Notification or Indication already registered 187- Linked List: return if item was added for `btstack_linked_list_add[_tail]` 188- btstack_run_loop_remove: return bool true if timer/data source was removed 189- segger-rtt: allow to configure with `SEGGER_RTT_PACKETLOG_*` directives, update to v6.54 190- GAP: support setting Link Supervision Timetout for outgoing Classic connections using `gap_set_link_supervision_timeout` 191- lwip: add download test files to http server demo 192 193### Changed 194- Linked List: return bool true if item was removed 195 196 197## Changes October 2019 198 199### Fixed 200 201### Added 202- `btstack_bool.h`: provide boolean type 'bool' via `<stdbool.h>` or as backport 203- provide `btstack_assert(condition)` 204- H4 Transport: avoid calling `hci_transport_h4_trigger_next_read` when transport is closed 205 206### Changed 207- libusb and posix ports: store bonding information in TLV 208 209 210## Changes September 2019 211 212### Fixed 213- L2CAP ERTM: assert that packet can be stored in fragment buffers in ertm 214- L2CAP ERTM: reject incoming connection if ERTM is configured as mandatory but not supported by remote 215- GATT Client: allow Write Without Response independent of other requests 216 217### Added 218- GAP: allow to reject GAP classic connection via gap_register_classic_connection_filter 219- GAP: support reading RSSI for Classic+LE using gap_read_rssi. Emits `GAP_EVENT_RSSI_MEASUREMENT` 220 221### Changed 222- Bluetooth and BTstack Error Codes and Events: collect status codes in bluetooth.h and events in btstack_defines.h 223- bluetooth.h: extract internal defintitions to respective protocol layers 224- Updated CC256x initscripts (CC256xB v1.8, CC256xC v1.2, CC256xC v1.2) 225 226 227## Changes August 2019 228 229### Fixed 230- POSIX, WICED, Windows, FreeRTOS run loops: handle time_ms overrun after 49 days 231- RFCOMM: accept incoming L2CAP connection in Basic mode if ERTM is enabled but not requested for this connection 232- RFCOMM: limit RFCOMM MTU by local L2CAP MTU for outgoing connections (only revelvant for ERTM) 233- L2CAP ERTM: stop timers on disconnect 234- L2CAP ERTM: fix sending of segmented SDUs 235- L2CAP ERTM: handle unsupported Information Response 236- SM: generate local nonce for confirm value in JW+NC+PK in Secure Connections Responder role 237 238### Added 239- `btstack_run_loop_base`: portable implementation of timer and data source management as base for platform specific implementations 240 241## Changed 242- FreeRTOS: use xQueueCreateStatic (static variant of xQueueCreate) if available for static memory-only setups 243- L2CAP ERTM: handle invalid Information Response (assume no extended features supported) 244- POSIX: use monotonic clock as timebase if available 245- HCI Transport H4/H5/EM9304 SPI: ignore block read/sent from UART driver when closed 246- HCI: Read Encryption Key Size after encryption was enabled 247- Errata 11838: 248 - GAP: gap_set_required_encryption_key_size allows to set the required key size, default = 16 (max) 249 - GAP: validate encryption key size to emit GAP Security Levels 250 251## Changes July 2019 252 253### Fixed 254- SM: Fixed regression introduced in f3582630 255- L2CAP: avoid reading l2cap signaling command len out of bounds 256- HCI Transport H4/H5/EM9304 SPI: fix payload size checks (also for 8/16-bit platforms) 257 258### Changed 259- SM: Start encryption upon receiving slave securiy request if bonded 260- hci: use 2 as HCI_INCOMING_PRE_BUFFER_SIZE in LE-only configuration for GATT Client 261 262--- 263 264## Changes June 2019 265 266### Changed 267- FreeRTOS: use freertos/.. prefix to include FreeRTOS headers if HAVE_FREERTOS_INCLUDE_PREFIX is defined 268- BNEP: add Connection Handle to BNEP_EVENT_CHANNEL_OPENED 269- Examples: renamed le_counter to gatt_counter and le_streamer to le_streamer_server to indicate suppport for GATT over BR/EDR 270 271### Fixed 272- BNEP: Bluetooth address is stored in little-endian format for all BNEP_EVENT_* 273- libusb: avoid use-after-free for SCO packets on disconnect 274 275### Added 276- example: pan_lwip_http_server using lwIP as network stack to implement PAN NAP service 277- platform/lwip/bnep_lwip.c: BNEP lwIP adapter that forwards packets between BNEP service and lwIP 278- ENABLE_GATT_OVER_CLASSIC enables support for GATT over BR/EDR in att_server 279 280--- 281 282## Changes May 2019 283 284### Changed 285- ESP32: Configure SCO over HCI after power up 286- btstack_tlv_flash_bank: support targets where a value cannot be overwritten with zero. When ENABLE_TLV_FLASH_EXPLICIT_DELETE_FIELD 287 is defined, an explicit delete field is used to indicate an invalid entry. 288 289### Fixed 290- SM: Avoid potential use-after-free on immediate disconnect (lookup connection via con handle instead of storing pointer) 291 292### Added 293- gatt_client: emit query complete event for signed write operation 294- hci_transport_h4: add workaround for flow control bug in CYW2070x, enable with ENABLE_CYPRESS_BAUDRATE_CHANGE_FLOWCONTROL_BUG_WORKAROUND 295 296--- 297 298## Changes April 2019 299 300### Changed 301- ESP32: use micro-ecc from 3rd-party as esp-idf removed it in their 3.3 release 302 303### Fixed 304- hci: pad LE Scan response with zeroes 305- SM: store local CSRK 306- ATT DB: call write callback for validated signed writes 307- ATT Server: abort signed write validation on incoming new request 308- Bluetooth SIG web scraping tools updated 309- libusb: compiles for FreeBSD 310 311### Added 312 313--- 314 315## Changes March 2019 316 317### Changed 318- use Makefile for stm32-f4discovery-cc256x port 319- le_device_db: add secure_connection argument to le_device_db_encryption_set and le_device_db_encryption_get 320 321### Fixed 322- SM: Use provided authentication requirements in slave security request 323 324### Added 325- port/stm32-f4discovery-cc256x: add support for built-in MEMS microphone 326- SM: Track if connection encryption is based on LE Secure Connection pairing 327- ATT DB: Validate if connection encrypted is based on SC if requested 328- att_db_util: support ATT_SECURITY_AUTHENTICATED_SC permission flag 329- GATT Compiler: support READ_AUTHENTICATED and WRITE_AUTHENTICATED permsission flags 330- ESP32: erase nvs flash is newer nvs version found 331- libusb: add support for nRF52840-PCA10056 running Zephyr hci_usb example 332- port/stm32-l073rz-nucleo-em9304 for Nucleo L073RZ with EM9304 DVK, replaces port/stm32-l053r8-nucleo-em9304 333 334## Changes February 2019 335 336### Changed 337- example/a2dp_sink_demo: use linear resampling to fix sample rate drift 338- btstack_audio: split interface into sink and source 339 340### Fixed 341- Crypto: fix lockup when stack is shutdown while waiting for result of HCI Command, e.g. LE Read Local P256 Public Key 342- SM: Avoid SM_EVENT_PAIRING_COMPLETE with ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION after successful pairing in responder role 343 344### Added 345- example/a2dp_sink_demo: add target role, support volume control on both devices 346- example/audio_duplex: playback audio audio source on audio sink (test audio path) 347- btstack_audio_embedded: implement audio source path 348 349--- 350 351## Changes January 2019 352 353### Changed 354- L2CAP: provide channel mode (basic/ertm) and fcs option in L2CAP_EVENT_CHANNEL_OPENED 355- RFCOMM: support L2CAP ERTM. Callbacks passed to rfcomm_enable_l2cap_ertm() are used to manage ERTM buffers 356 357### Added 358- L2CAP: emit L2CAP_EVENT_ERTM_BUFFER_RELEASED if ERTM buffer not needed/used anymore 359- L2CAP: add fcs_option to ERTM config l2cap_ertm_config_t 360- HCI: validate advertisement data length field when generating GAP_EVENT_ADVERTISING_REPORT 361- ad_parser: validate data element length fields in ad_iterator_has_more 362- Raspberry Pi 3 A+/B+ port in port/raspi, starts without power cycle 363 364### Fixed 365- HCI: release outgoing buffer on disconnect if waiting to send another ACL fragment 366- POSIX: use correct baudrate enums for baud rates higher than 921600 (Linux) 367- Crypto: directly process queued crypto operation on HCI result 368 369--- 370 371## Changes December 2018 372 373### Added 374- SM: generate and store ER / IR keys in TLV, unless manually set by application 375- hci_dump: support PacketLogger or BlueZ format output via SEGGER RTT Channel 1 Up 376 377### Fixed 378- SM: fix internal buffer overrun during random address generation 379 380## Changes November 2018 381 382### Added 383- GAP: gap_le_connection_interval provides connection interval for conn handle 384- Nordic SPP Service Server: GATT service that emulates a serial port over BLE based on Nordic Semiconductor documentation. 385- uBlox SPP Service Server: GATT service that emulates a serial port over BLE based on uBlox documentation. 386- SM: ENABLE_LE_CENTRAL_AUTO_ENCRYPTION triggers automatic encryption on connect to bonded devices 387- SM: generate and store ER / IR keys in TLV, unless manually set by application 388 389### Fixed 390- SM: prevent random address updates if gap_random_address_set was used 391- SM: fix internal buffer overrun that can cause storing of bonding information to fail 392- SM: ignore Slave Security Request after sending own Pairing Request 393- L2CAP: fix use after free on disconnect if ERTM is enabled 394- HFP: Handle multiple commands/responses in single RFCOMM packet 395- Memory Pools: clear all buffers before use 396 397--- 398 399## Changes October 2018 400 401### Added 402- SDP Server: queue incoming connections when already connected instead of rejecting them 403- 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. 404- HIDS Device: GATT service that exposes HID reports intended for HID Devices, like keyboard and mouse. 405 406### Fixed 407- HCI: fix bug in gap_inquiry_stop that triggered additional GAP_EVENT_INQUIRY_COMPLETE instead of stopping the inquiry 408- L2CAP: fix issue with outgoing connection before read remote supported complete when other channels exist 409- L2CAP ERTM: allow SDU of szie MPS in first packet that contains L2CAP SDU Length 410- L2CAP ERTM: fix memory corruption triggered if local_mtu > mps 411- L2CAP ERTM: fix outgoing fragment management 412- HFP: decline incoming RFCOMM connection after outgoing connection was started 413- AVRCP: fix crash on disconnect of connection established by remote 414 415--- 416 417## Changes September 2018 418 419### Fixed 420- HCI: Error creating outgoing connection (e.g. Connection Limit Exceeded) now handled 421- L2CAP: Error creating outgoing connection (e.g. Connection Limit Exceeded) now handled 422- L2CAP: Evaluate 'can send now' on HCI Disconnect as ACL buffers in Bluetooth Controller have been used for the closed connection are freed implicitly 423- L2CAP: Check can send now before sending extended information requeste needed for ERTM mode 424- L2CAP: Use valid signaling identifier for L2CAP Connection Parameter Update Request 425- 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 426- RFCOMM: Avoid use-after-free on channel finalize 427- GATT Client: stop timer on disconnect - fixes use after free / crash 428 429### Added 430- A2DP Source: Support stream reconfiguration (a2dp_source_reconfigure_stream_sampling_frequency) 431- 3rd-party: yxml is used for PBAP vCard list parsing 432- cc256xC: new v1.1 init scripts 433 434--- 435 436## Changes August 2018 437 438### Added 439- PBAP: added pbap_get_phonebook_size() to get phonebook entry count 440 441### Fixed 442- GATT Server: Allow enable Notifications/Indication with Write Command. Fixes issue with some Android devices. 443- SM: fix pairing for Secure Connections with Bonding if remote sends additional keys 444- SM: drop LTK flag from Pairing Response for Secure Connections 445- L2CAP: fix emitted L2CAP_EVENT_CONNECTION_PARAMETER_UPDATE_REQUEST 446 447## Changes June 2018 448 449### Added 450- btstack_audio.h: application level API for audio playback and recording 451- embedded/hal_audio.h: low-level API for audio playback and recording 452- HID Device: hid_device_connect(..) function 453- ESP32: implement hal_audio 454- DA14585: support for Dialog Semiconductor DA14585 LE-only controller 455- Raspberry Pi 3 + Raspberry Pi Zero W port in port/raspi 456 457### Changed 458- Errata 10734: 459 - SM: Generate new EC Public Keypair after each pairing 460 - SM: Abort failure with DHKEY_CHECK_FAILED if received public key is invalid (instead of unspecified error) 461- btstack.h: only include classic headers if ENABLE_CLASSIC is defined 462- windows: ignore virtual Bluetooth adapter provided by VMware 463- Replaced HCI_PACKET_BUFFER_SIZE with HCI_INCOMING_PACKET_BUFFER_SIZE and HCI_OUTGOING_PACKET_BUFFER_SIZE 464 465--- 466 467## Changes June 2018 468 469### Fixed 470- HFP: Fix Wide Band Speech bit in SDP record for both HF/AG. Missing bit prevents macOS from using mSBC 471- ATT Server: send ATT_EVENT_HANDLE_VALUE_INDICATION_COMPLETE with status ATT_HANDLE_VALUE_INDICATION_DISCONNECT on disconnect 472- AVRCP Controller: fix parsing of now playing info 473 474### Changed 475- ATT Server: ATT_HANDLE_VALUE_INDICATION_DISCONNECT is delivered to service handler if registered 476 477### Added 478- ATT Server: packet handler field added to att_service_handler_t to receive: connect/disconnect, atu exchange, indication complete 479 480--- 481 482## Changes May 2018 483 484### Added 485- GAP: re-encrypt outgoing connection if bonded 486- ATT Server: wait until re-encryption is complete 487- GATT Client: wait until re-encryption is complete 488- ATT Server: added att_server_request_to_send_notification and att_server_request_to_send_indication 489- GATT Client: if ENABLE_GATT_CLIENT_PAIRING, GATT Client starts pairing and retry operation on security error 490 491### Changed 492- ATT Server: att_server_register_can_send_now_callback is deprecated, use att_server_request_to_send_notification/indication instead 493 494### Fixed 495- SM: Fix LE Secure Connection pairing in Central role 496- le_device_db_tlv: fix seq nr management 497- SM: improve le_device_db lookup and storing of IRK 498- GATT Server: fix lookup for Client Characteristic Configuration in services with multiple Characteristics 499- RFCOMM: emit channel closed on HCI/L2CAP disconnect after sending DISC while expecting UA 500 501--- 502 503## Changes April 2018 504 505### Added 506- Crypto: btstack_crypo.h provides cryptographic functions for random data generation, AES128, EEC, CBC-MAC (Mesh) 507- SM: support pairing using Out-of-Band (OOB) data with LE Secure Connections 508- Embedded: support btstack_stdin via SEGGER RTT 509 510### Changed 511- att_db_util: added security requirement arguments to characteristic creators 512- SM: use btstack_crypto for cryptographpic functions 513- GAP: security level for Classic protocols (asides SDP) raised to 2 (encryption) 514 515### Fixed 516- HFP: fix answer call command 517- HCI: fix buffer overrun in gap_inquiry_explode 518- SDP: free service record item on sdp_unregister_service 519 520## Changes March 2018 521 522### Added 523- GAP: allow to limit number of connections in LE Peripheral role with gap_set_max_number_peripheral_connections 524- ATT Server: support for delayed ATT read response, see example/att_delayed_read_response.c 525- ATT Server: allow to specify security requirements seperately for read/writes. .h files need to be regenerated 526 527### Fixed 528- RFCOMM: fix infinite loop on L2CAP connection error (regression from 4c3eeed1) 529- HSP HS: accept incomming SCO connection 530- SM: fix iteration over LE Device DB entries for bonding and address resolving 531- SM: store pairing information only if both devices have requested bonding 532 533--- 534 535## Changes February 2018 536 537### Added 538- GATT Client: gatt_client_request_can_write_without_response_event() causes GATT_EVENT_CAN_WRITE_WITHOUT_RESPONSE 539- SM: new event SM_EVENT_PAIRING_COMPLETE 540- GAP: support iteration over stored Classic link keys: gap_link_key_iterator_init, gap_link_key_iterator_get_next, gap_link_key_iterator_done 541- GAP: add gap_delete_all_link_keys 542 543### Changed 544- GATT Client: round robin for multiple connections 545- ATT Dispatch: round robin for ATT Server & GATT Client 546- L2CAP: round robin for all L2CAP channels (fixed and dynamic) 547- btstack_link_key_db: addition functions for link key iteration 548- GAP: LE scanning enabled not reset on HCI Reset -> can be enabled before HCI Power Up 549- CSR: set all keys in psram instead of default 550 551### Fixed 552- tc3556x: fix startup after baud rate change 553 554--- 555 556## Changes January 2018 557 558### Added 559- Port for Windows with Zephyr HCI Firmware connected via serial port 560- em9304: upload patch containers during HCI bootup 561- Makefile for STM32-F4Discovery port 562- support for console out via SEGGER RTT 563- LE Data Channels example in BTstack and [iOS example on GitHub](https://github.com/bluekitchen/CBL2CAPChannel-Demo) 564- LE Streamer Client can send as fast as possbile as well 565- L2CAP: option to limit ATT MTU via l2cap_set_max_le_mtu 566 567### Changed 568- HCI: allow to set hci_set_master_slave_policy (0: try to become master, 1: accept slave) 569- GAP: gap_set_connection_parameters includes scan interval and window params 570- GATT Client: GATT_EVENT_MTU indicates max MTU 571- ATT DB Util: attribute handle is returned for new Services and Characteristics 572 573### Fixed 574- Windows: retry serial port operations if not all bytes have been read/written 575- HFP: avoid buffer overflows setting up messages 576- SBC Decoder: improved error handling for invalid SBC audio data 577- GAP: fix Connection Parameter Response in Central role 578- ATT DB Util: update pointer to database in case of realloc 579- GATT Client: set UUID16 field if 16-bit UUID is stored as UUID128 580- GAP: release HCI Connnection after gap_le_conne 581- ATT: Exchanged MTU is propagate to ATT Server and GATT Client 582 583--- 584 585## Changes December 2017 586 587### Added 588- Introduced btstack_network.h network interface abstraction 589- btstack_network_posix implementation using Linux tun/tap interface 590- WICED: support for btstack_stdin (HAVE_STDIN) 591- 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. 592- TLV: global TLV instance available via btstack_tlv_get_instance() (src/btstack_tlv.h) 593- TLV: POSIX implementation that appends to a file on disk (platform/posix/btstack_tlv_posix.c 594- LE Device DB TLV: overwrite oldest entry if no free entries available 595- SM: allow to set fixed passkey in display role using sm_use_fixed_passkey_in_display_role 596- Example/hid_host_demo with HID parser and support for basic US keyboard layout 597- 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 598- Port for Apollo2 MCU with EM9304 (ports/apollo2-em9304) 599 600### Changed 601- panu_demo: uses btstack_network.h now 602- WICED: configure printf to replace Linefeed with CRLF 603- SBC: split btstack_sbc_bludroid.c into seperate encoder and decoder implementations 604 605### Fixed 606- RFCOMM: support connection requests during connection failure 607- L2CAP: support connection requests during connection failure 608- L2CAP: fix default remote MTU as 672 instead of 48 (Minimal MTU) 609- HCI: avoid double free during halting 610- SM: fixed reconnect using legacy pairing in slave role 611 612 613