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