Documentation for pre-release v4.2-beta1 is available at https://docs.espressif.com/projects/esp-idf/en/v4.2-beta1/

ESP-IDF v4.2 is a minor update for ESP-IDF v4.1.

This is the list of changes since release v4.1:

Major New Features

Secure Boot V2 support (RSA based) added for ESP32 V3
Support for ESP32+ATECC608A (ESP32-WROOM-32SE) platform along with sample application
Added feature to utilize residual IRAM as data memory for ESP32 single core configuration
Added support of Bluetooth 5.0 for ESP32
Added ESP-HID Component
WiFi: Added and utilize WPA3/WPA2 Mixed mode Authtype
WiFi: Added support of multiple phy init data
WiFi: Added wpa_supplicant parsing support for WEP40 key
ESP-WIFI-MESH: Support chain topology
ESP-WIFI-MESH: Support mesh network power save function
Support for ESP32-S2 SoC
- Wi-Fi
  - Wi-Fi driver
  - Wi-Fi modem sleep
  - Wi-Fi with automatic light sleep
- Security
  - Flash & PSRAM encryption
  - RSA accelerator
  - AES accelerator
  - SHA accelerator
  - Digital signature
  - HMAC
- Peripherals
  - UART
  - Timer group
  - GPIO
  - SPI Master
  - SPI Slave
  - I2C
  - I2S
  - LEDC
  - PCNT
  - SigmaDelta
  - RMT
  - USB Device
  - Touch sensor
  - ADC
  - DAC
  - SD card over SPI
  - Ethernet over SPI
  - RTC interrupts
  - Brownout detector
  - Temperature sensor
  - ULP coprocessor (RISC-V)
- System features
  - Cache
  - esp_timer
  - SPI Flash
  - PSRAM — 2MB
  - I/D RAM separation
  - OTA
  - RTC Slow clock selection (e.g. 32k XTAL)
  - Task, interrupt watchdogs
  - Efuse API and espefuse.py
  - Console over USB
  - DFU flashing
  - CDC flashing
- Build system and tools
  - Building the project using CMake (build, flash, monitor, menuconfig)
  - "idf.py size"
- Sleep modes
  - Deep sleep
  - Light sleep
  - DFS
  - Automatic light sleep and esp_pm power management
  - Light sleep GPIO wakeup
- Debugging
  - Core dump
  - app_trace
  - Systemview
  - OpenOCD
- Protocols
  - Modbus
  - Provisioning
  - Other protocols on top of TCP/IP

Known Issues

The esp-2020r2 toolchain has been added in this release which includes some fixes for C++ exceptions, a fix for -O2 optimization of volatile word accesses, and an improved PSRAM fix. Extended stress testing of Wi-Fi & BT coexistence with heavy PSRAM use show there is a difficult to reproduce issue with the updated PSRAM fix. It is possible to roll back to the esp-2020r1 toolchain release by running git revert --no-edit 298f23c9 in the ESP-IDF directory, then re-run the install.sh/install.bat/install.ps1 and . export.sh/export.bat/export.ps1 steps as described in the Get Started guide. This issue will be fixed in the v4.2 final release.
A new macro to call a function with a user-allocated stack has been added but is non-functional
Secure Boot is not yet supported on ESP32-S2. Will be included in the v4.2 final release.
Early boot Random Number Generation is not enabled on ESP32-S2. The Flash Encryption feature should not be used in this release, unless keys are generated on the host and burned to eFuse manually. Do not rely on any random numbers generated before Wi-Fi is enabled. Early boot RNG for ESP32-S2 will be enabled before the v4.2 final release.
SPP: Not able to use BT SPP because exception happens when init BT SPP.
Light sleep: Wi-Fi light sleep is not stable on ESP32-S2. Wi-Fi could disconnect from AP in light sleep.

Bluetooth

Classic Bluetooth

Controller

Fixed the issue that when host runs different core from controller and sleep enabled，HCI timeout may occur
Added user invisible kconfig for BT MAC offset (#5320)
Fixed time jitter in FHS during role switch
Fixed time jitter in first POLL packet during role switch
Fixed failure in receiving EDR packet after role switch
Fall back to main XTAL as Bluetooth sleep clock when EXT 32K CRYS is configured but not detected
Set non-zero initial value for BT sleep clock cycle to avoid div-by-zero error in function "btdm_us_2_lpcycles" when BT modem sleep is not enabled
Fixed assert when creating connection cancellled
Fixed ASSERT for RXDESC
Fixed ASSERT in ld_acl at line 302 forclkoff1 and localval
Fixed ld_acl schedule issue to parity shift
Fixed ASSERT in ld_pscan.c at line 1032
Fixed free lmp tx buf in EM in the procedure of handling LMP_detach_Req when not received the last acknowledge from peer device and separate them by ACL State
Fixed no mode change event reported when slave initiates unsniff procedure and a transaction collision occurs
Fixed interrupt WDT timeout due to interrupt disabled period
Fixed Connection fail in loop
Fixed ASSERT(25,0) in lc_task.c
Disabled frequent warning log in ld_acl
Fixed future events scheduling error in case of wifi and bluetooth
Fixed clk offset error in ld_acl.c

Bluedroid

Separate BTA_JV_L2CAP for less bin size
Fixed cases having fallback to link up event
GAP: Fixed error EIR type in config eir event
GAP: fixed the issue when calling esp_bt_gap_remove_bond_device to remove a bonded device and then calling esp_bt_gap_get_bond_device_list, it may return invalid Bluetooth address (#5395)
SPP: Added API esp_spp_stop_srv()
SPP: Fixed task watchdog when running SPP example in VFS mode
SPP: Fixed the error parameter in spp examples (#5408)
HID-Host: Added HID Host support in Bluedroid
A2DP: Fixed the issue that A2DP_SINK example cannot successfully compile when Compiler Optimization Level is performance (O-2)
AVRCP: Replaced U+0092 with regular apostrophes in avrc_defs.h (#4667)
HFP-AG: Fixed connection failure and crash when receiving unknown AT command
HFP-AG: Fixed error of return line in AG API (#5554)
HFP-AG: Fixed AG audio crash (change the return position)
HFP: Enabled PCM config in menuconfig and controller

Bluetooth Low Energy

Controller

Added BLE connect parameter check
Fixed channel map instant reverse
Fixed ASSERT(64,0) in rwble.c
Fixed for HCI desync deadlock issue in BLE controller
Fixed ble crash issue triggered by ble event irq miss(0x20000) (d2a1d18d)
Fixed the crash when controller disabled and then re-enabled for ble
Fixed the missed channel map update when the slave latency is greater than 0.
Fixed the missed channel map update when the instant value is 0

Bluedroid

Added API to query the number of available buffers for the current connection
Consider link_xmit_data_q in congest events to prevent excessive memory usage
Changed HCI task size back to 2048
Fixed the issue of incomplete data packets caused by disordered acl data packets
Fixed ble memory leak issue, buff_semaphore was not released
Added HID Host and Device support in Bluedroid
Added some general HID utilities and definitions to help integrate with other stacks and native USB
Fixed the issue that bluedroid task pinned_to_core doesn't take effect
Authentication fixes in Legacy and Secure Connection
Fixed don't dequeue the command queue after process the read_by_type_req
Fixed notify malloc failed when testing multi-connection notify performance
Fixed client no BLE_AUTH_CMPL_EVT when client proactively initiate an encryption request after device restart
Fixed btc disable crash sometimes
Fixed the state not synchronized between controller and host when disconnected

Blufi

Reply with an error response when the format of the received data packet is wrong

NimBLE

Added menuconfig option for NimBLE host flow control
Added Non-Resolvable private address (NRPA) support
Added NimBLE config options in sdkconfig.rename
Added header guards and closing bracket conditional for c++ in ble_hs_pvcy.h (espressif/esp-nimble#12)
Added ble_hs_lock in ble_gap_unpair: upstream PR!584
Added Host based privacy (RPA) feature support
Added IRAM allocation provision under nimble_platform_mem_malloc()
Fixed repeated pairing failure in RPA (#5530)
Fixed potential issue with strncpy in os_mempool.c: upstream PR!843
Included changes in blecent example: upstream PR!702
Fix checking for NOP in ble_hs_hci_rx_evt: upstream PR!738
Fixed check for static random address & add MSYS_1 in menuconfig
Fixed NIMBLE_HS_FLOW_CTRL_TX_ON_DISCONNECT in esp_nimble_cfg and bleprph README
Fixed build failures due to non static declarations in RPA feature (#4413)
Reset master and slave states on host reset
Use macros for log level filtering which reduces the size of the compiled binary, PR: espressif/esp-nimble#6
Fix NULL pointer passed as a parameter: upstream [PR!701)(https://github.com/apache/mynewt-nimble/pull/701)
Pairing procedure abort on unexpected req: upstream PR!710
Fix conn flags after pairing: upstream PR!730
Remove notification for update process timeout (Vol 6, Part B, section 5.2 ): upstream PR!782
CCCD related fixes: upstream PR!790 and PR!804
Host based Privacy (RPA) related fix: espressif/esp-nimble#7

ESP-BLE-Mesh

Miscellaneous modifications for Provisioner
- Support Provisioner persistent functionality
- Added a function to set Provisioner static oob value
- Added a function to set Provisioner unicast address
- Added a function to provision devices with fixed address
- Added a function to store node composition data
- Added a function to get node with device uuid
- Added a function to get node with unicast address
- Added a function to delete node with device uuid
- Added a function to delete node with unicast address
- Added a function for Provisioner to update local AppKey
- Added a function for Provisioner to update local NetKey
- Fixed Provisioner entering IV Update procedure
- Fixed Provisioner failed to publish messages
- Provisioner ignores msg from removed node
- Fixed Provisioner provisioning deadlock
- Checks if the AppKey exists before deleting it
- Modified the Provisioner disable function
- Add parameters for Provisioner binding AppKey comp event
- Fixed not reset transport info when node is removed
- Removed BLE_MESH_MAX_STORED_NODES option
- Changed to continue node info restore even if failure happens
- Added check if assigned node address is duplicated
- Associates replay protection list size with nodes count
- Updated next alloc address when node info is added
- Continue notifying unprovisioned device beacon to application layer
- Add a function to get the entry of the nodes table (#5397)
- Use same functions for node composition data store/restore
- Added functions to get node information with node name
Synchronized a few Zephyr BLE Mesh updates
Support using a specific partition for BLE Mesh
Added a function to de-initialize BLE Mesh stack
Fixed use-after-free issue when de-initialize mesh
Fixed not free beacon timer when de-initialize mesh
Fixed de-initialize error when using NimBLE host
Added mutex for mesh related timer operations
Fixed an issue which may cause client failed to send messages
Use bt_mesh.flags to indicate mesh device role
Callback RSSI of received mesh provisioning packets
Change some stack log level from debug to info
Fixed node ignoring relay messages issue
Fixed compile warning when proxy related macros are disabled
Clean up BLE Mesh stack included header files
Fixed compile warning when BT log is disabled
NULL can be used if client message has no parameters
Initialize BLE Mesh stack local variables
Support using PSRAM for BLE Mesh mutex, queue and task
Added an option to enable using memory from PSRAM
Allow sending messages with maximum 377 octets payload
Unified client application and lower transport layer timeout
No timeout for client message to non-unicast address
Fixed timer start when sending client acknowledged messages
Fixed client local parameters not initialized
Calculates incomplete message timeout based on message info
Added check of buf->ref before decrementing buffer ref count
Used the right net_idx & app_idx for publish
Used the right netkey during iv update
Fixed time scene wrong spelled macro name
Added length check for some mesh operations
Reworked provisioning pdu length check
Added proxy configuration pdu length check
Fixed not erasing mesh node information completely
Added an option to fix node nvs information restore
Added missing #ifdef __cplusplus
Fixed using a UTF-8 comma in Kconfig
Fixed not updating provisioner address in fast provisioning
Fixed ignoring messages when fast provisioning is enabled
Fixed compile error when including from C++ files
Support for BLE advertising simultaneously when mesh is working
Added init flag for friend init/deinit
Fixed compile error when -O2 (performance) is chosen
not ignore messages from the nodes whose addresses are not in the provisioning database
Removed the fix patch for Bluetooth Mesh Android App v1.1.0
Fix the issue of using old config for duplicate scan
Fixed the issue of not using pre-initialized private key
Added check of the result of creating timer
Defined an application macro for invalid company ID
Removed relay option dependency
Do not #define bool when compiling in C++ (#5100)
Removed boolean type definitions
Added checking model status with variable length
Added functions for model subscribing/unsubscribing group addresses locally
Fixed wrong log output when using bt_hex
Fixed the issue that RSSI of the received message is always 0 (#5505)
Added checking if subnet exists before updating beacon_sent
Fixed compile error when only proxy enabled
Updated send_ttl when receiving a message (#5300)
Added two application macros for TTL
Added an option of using IRAM for memory allocation
Reworked using dev flag to check scan status
Fixed receiving health current status incorrectly
Optimized calling of client model related functions

Wi-Fi Coexistence

Fixed watchdog timeout when sleep enabled
Fixed misspelling in Kconfig
Fixed A2DP stuck after creating another connection
Adjust coexist scheme when BT is in connected status
Fixed wakeup delay when DFS is enabled
Optimized WiFi/BT coexist sleep
Added coexist API to enable BLE connection dynamic priority

Wi-Fi

Added and utilize WPA3/WPA2 Mixed mode Authtype
Added support of multiple phy init data
Added wpa_supplicant parsing support for WEP40 key
Added TX packets size check
Added esp_wifi_get_tsf_time() API to get the tsf time
Added check for Wi-Fi stop when calling esp_wifi_deinit
Added sending sta connection event again after ap sent disconnect event
Added API of setting/getting inactive time
Added new API esp_wifi_ap_get_sta_aid
Added an API for peripherals to set callbacks to skip light sleep when WiFi TSF is active
Added TBTT update when AP reset TSF
Added API to get available internal heap size
Added softap example channel configuration
Removed AUTH_CHANGED reason code logic
Fixed the issue when calculating the PMK, the local rx beacon time increment is 0
wpa_supplicant: Support for mbedtls tls handshake
wpa_supplicant: Fixed invalid pointer deference and memory leak
wpa_supplicant: Fixed inter operability issue with freeradius version 3.0.21 and openssl 1.1.1f when internal tls client is used which requires extension elements in client hello
wpa_supplicant: Fix WPA3 and WPA2 transition related failures
wpa_supplicant: Fixed compilation errors when USE_MBEDTLS is disabled
wpa_supplicant: Ported dpp feature from supplicant
wpa_supplicant: Fix formatting of file esp_wpa3.c
wpa_supplicant: Allow NULL-padded WPS attributes
wpa_supplicant: Allow building with mbedTLS integration but no hardware MPI (#5321)
wpa_supplicant: Added wpa_supplicant debug logging as a configurable option (#3839)
wpa_supplicant: Fix SAE test-case failure on mbedtls version udpate
WPS: fixed handling of multiple AP credentials in WPS
Fixed WPS config for support with gnu++11 as well as c99 (#4625)
esp_wps.c: Fixed datatype for wps task handle
Fixed the issue that API esp_wifi_sta_get_ap_info returns actual values of group
Fixed an crash in executing wifi deinit in softap + sta mode and AMPDU is on
Fixed the issue that sniffer fails to work during mode switch
Place the Vendor Specific element at the end according to the protocol
Fixed the memory leak caused by WiFi stop
Fixed the crash when wifi stop after deinit
Fixed the issue that softap will no prompt if the STA is powered off or the AP does not receive disassoc/deauth
Fixed the issue when station connects to hidden AP, fails to update rssi value of hidden AP
Fixed setting channel when Wi-Fi is in NULL mode
Fixed a crash during WEP shared auth
Disabled WiFi API parameter checking log
Fixed select_waiting assert and crash after reapplying for UDP socket when UDP is turned off
Fixed the issue that information of scanned AP will be saved only when the current scanning channel is the same as AP's channel
Avoid parsing RSN/WPA IE's after connection
Configure bandwidth and phy mode to store NVS
Now returns an error if the setting AP's channel is out of range
Fixed error in printing level in wifi log
Disabled wpa_supplicant TLS 1.2 support by default due to issues with some Enterprise Authentication Servers
Fixed esp_wifi_stop crash without calling init
Fixed obsolete interface gethostbyname
Fixed the bug for softAP update second channel wrong
Fixed country code query when policy change from manual to auto
Fixed internal scan data struct definition, changed wifi_scan_time_t from union to struct
Enable WPA3 & PMF by default
Fixed WPA3 Auth timeout issue in BLE coexistence scenario
Fixed memory leak in wpa3
Fixed AP switch to adjacent channel without disconnect (CVE-2020-12638)
Fixed wpa_supplicant memory leaks and invalid memory access
Fixed a timeout issue in the EAPOL four-way handshake
Optimized four-way handshake failure time
Fixed esp_wifi_set_max_tx_power description
Removed wifi tx buffer limits
Fixed addba ssn and send bar for first ampdu
Fixed interrupt handle psram variable error (#5354)
Fixed the issue of regdomian update
Fixed an issue when setting TX DMA buffer above 32 would not take effect
Fixed WPA memory leak in softap mode
Moved esp_phy_common_clock_disable into periph_ctrl and put it into IRAM
Added esp_wifi_ap_get_sta_aid
Fixed AP power save buffer issue by returning no memory error code is power save buffer is not enough
Fixed scan saves wrong RSSI value
Added esp_wifi_statis_dump to dump the key WiFi statistics
Optimize WiFi TX

ESP-WIFI-MESH

Support chain topology
Add esp_mesh_set_topology and esp_mesh_get_topology
Support mesh network power save function
Add esp_mesh_enable_ps and esp_mesh_disable_ps
Add esp_mesh_is_ps_enabled and esp_mesh_is_device_active
Add esp_mesh_set_active_duty_cycle and esp_mesh_get_active_duty_cycle
Add esp_mesh_set_network_duty_cycle and esp_mesh_get_network_duty_cycle
Add esp_mesh_get_running_active_duty_cycle
Add mesh PS option to the add announcement packet
esp_mesh_set_type supports MESH_IDLE and MESH_STA
Remove coexist warnings in ESP_WIFI_MESH
If the root is specified (FIXED-ROOT) by set type or set parent, change ie.mesh_type to MESH_ROOT before connect to router
Release esp_mesh_recv_toDS when the root becomes non-root
Fix esp_mesh_deinit blocking issue
Remove coexist warnings for ESP_WIFI_MESH
Add an example showing internal IP capable mesh network

ESP-NOW

Fixed ESP-NOW API random crash
Fixed the crash issue when fetching peer after delete cur_peer
Supported ESPNOW + PMF co-existance

Smartconfig

Airkiss: Fixed bug where connection would timeout but success was returned (#3362)
Fixed the bug that airkiss find hidden AP fail

Ethernet

Added the support of pin emac task to core
Added ETH_MAC_FLAG_WORK_WITH_CACHE_DISABLE flag to make Ethernet driver
possible to work when cache disabled (#4635)
Added ENC28J60 Ethernet Driver (#4435)
Ensure that eth_driver handle is allocated in internal RAM (#4635)
Fixed potential null pointer dereference in ethernet driver ( #4890)
Ensure that calling esp_eth_stop() stops the EMAC hardware layer
Improved reliability of ethernet driver start/stop/uninstall/install
Insert mininum assert time for PHY HW reset (#5528)
Fixed potential task watch dog timeout

Security

Added platform independent CMake signing
secure boot: Fix anti-fault value if hash is shorter than curve
optimize AES-GCM via enabling HW acceleration for GCM by default
HMAC: adding upstream message support
Enable flash encryption by setting FLASH_CRYPT_CNT to max
SHA: add fallback for when memory alloc fails
ESP32-S2: Added the support of disabling legacy boot mode & ROM remap modes if either Secure Boot or Flash Encryption is on

Peripheral Drivers

ADC: Disabled the synchronization operation function of ADC1 and DAC
ADC: Fixed adc io pullup/pulldown initialization bug
GPIO: Fixed light sleep can't be awoken by GPIO issue
I2C: Added check whether SCL and SDA are on different pins
I2C: Made data argument of i2c_slave_write_buffer const
I2S: Fixed issue: ADC read values inverted (#4557)
I2S: Fixed issue: i2s_comm_format_t configuration parameter does not match the TRM (#4522)
I2S-ADC: Fixed issue: GPIO may not configured properly when ADC is used with I2S
I2S, PCNT: Cleaned up public header
MCPWM: Fixed init MCPWM Fault line via config struct (#5491)
MCPWM: Fix fault pin initialization issue (#5491)
PCNT: Add pcnt_isr_unregister new interface
PSRAM: Fixed the read id failure for 16mbit PSRAM
PSRAM: Added support for esp32-pico-v3-02
RMT: Fixed missing 0x in rmt_ll.h (#4760)
RMT: Fixed the breaking change: application needs to call rmt_driver_install before rmt_config (#4664)
RMT: Fixed the breaking change: Do not support memory block count > 1 (#4959)
RMT: Supported using REF_TICK as channel clock source
RMT: Disabled carrier feature by default
RTCIO: Fixed the issue sometimes hold cannot be disabled (#4600)
SDIO: Fixed compilation error on verbose level (#4786)
SPI: Supported sharing SPI bus among drivers
SPI: Fixed the memory accessed while cache disabled issue in the bus lock when log level is verbose
SDSPI: Supported mounting multiple SD cards and using polling transactions to increase reading speed
TWAI: Fixed issue that some program logic are placed in assert()
UART: Fixed uart_set_line_inverse issue (#4581)
UART: Fixed the issue of missing txfifo reset
UART: Fix RXFIFO_CNT bug on ESP32 (#5101)
periph_ctrl: Added LL for clock and reset control
periph_ctrl: Added reference counter in periph_ctrl
periph_ctrl: moved esp_phy_common_clock_disable from WiFi, BT

Core System

Added alloc failed hook with optional abort option
Added semi-colon to esp_event_loop_create(...) (https://github.com/espressif/esp-idf/pull/4711/files)
Added support of LoadStore Exception Handlers
Added a Kconfig option - Number of attempts to repeat 32k XTAL calibration
Added soft solution for esp32 eco3 live lock issue
Added Task Watchdog backtrace printing
efuse: Added support of mac address allocation for ESP32-S2
efuse: Add new esp_efuse_write_field_bit() convenience function
efuse: Add 'disable Download Mode' & ESP32-S2 'Secure Download Mode' functionality
efuse: Fixed get_coding_scheme() when CONFIG_SECURE_FLASH_ENC_ENABLED and LOG_LEVEL is Debug (#4862)
efuse: Added an API to return the efuse descriptor for a key block's purpose field
efuse: Don't need to burn WR_CRYPT_CNT if CRYPT_CNT is already max
efuse: Add some fields in efuse_table and update esp_efuse_get_pkg_ver()
Fixed case when alarm_reg > counter_reg but FRC_TIMER_INT_STATUS is not set (#2954)
Fix esp_timer_impl_set_alarm() when CPU and APB freqs are changed (#2954)
soc: clear PHY status when cpu start
soc: add hal api to set exception vector table base address
soc: added hal api to set exception vector table base address
soc: Separates soc component into abstraction, description, and implementation files
heap: added aligned alloc implementation on multi_heap layer
heap: added alloc failed hook and configuration options
heap: pushed down all the aligned_alloc / free implementation
heap: added rtc fast memory region to dynamic memory pool
heap: Only fill new heaps with FREE_FILL_PATTERN on init if Comprehensive poisoning is enabled, allowing faster boot in other situations (especially when PSRAM is used)
esp_timer: Added implementation based on TG0 LAC timer
esp_timer: Create esp_timer as a separate component + LAC timer + SYSTIMER for ESP32-S2
log: Use proper API to get Tick Count in esp_log_timestamp
Fixed accessing some files from 2nd part of the bootloader
shared_stack: fixed watchpoint placement on shared stack
shared_stack: using watchpoint 1 to monitor the shared_stack instead of watchpoint 0
ESP-Event: added support of esp_event multiple registrations
Fixed compilation error, add missing gpio_periph.h header (#4797)
atomic: support fetch_and, fetch_and and fetch_xor
Create abstraction layer for cpu related operations
shared abort panic with port layer
let panic handler break on debug mode on software abort
suppress reason display on software abort panic
retain backtrace no space
Fixed case when elf file SHA256 should be printed by panic handler while cache is disabled
xtensa: add a script for parsing CPU traces (TRAX)
xtensa: fix sign-conversion warning (#4965)
multi_heap: ensure that malloc(0) return NULL pointer in any poisoning configuration
watchdog: Add LL (low-layer) and HAL (hardware abstraction layer) for watchdog timers
systimer: add HAL layer
log: added new macros to log when the cache is disabled
Console: Don't return NULL on 0 length input (#4926)
console_repl: Changed config structure to support different devices, added uart param to config structure (#4845)
esp_system: restored weak esp_reset_reason functions
pthread: Used INTERFACE in target_link_libraries for vPortCleanUpTCB wrapper
esp_efuse: Updated esptool and add reedsolo and bitstring into requirements.txt
esp_ipc: Moved esp_ipc to new component
intr_alloc: don't using esp_log in ISR context, using ISR version of critical section
Reduce using ESP_EARLY_LOGx and move some code after the stdout initialization (#5343)
Added psram stack check in backtrace
Added brownout detector HAL for esp32 and ESP32-S2
Enabled brownout reset for esp32 rev. 1 and above

Debugging

core dump: Disable core dump to flash if stack in PSRAM option is enabled
core dump: fixed coredump data overwriting due to 'TaskSnapshot_t' and 'core_dump_task_header_t' difference
core dump: Fixes size of memory region used by espcoredump.py
app_trace: Added support for multi-core traces in single file to SystemView processing scripts
panic handler: Fixed printing of ELF file SHA-256 if cache is disabled
Make espcoredump more resilient when decoding specific thread stack (#4865)
app_trace: Add coverage generations by gcovr
gcov: Fixed APP CPU syscall table

FreeRTOS

Optimized task selection on single core configurations
spin_lock: added new spinlock interface and decoupled it from RTOS
Added feature to utilize IRAM memory using exception handlers for unaligned access fixups
fpu: Enable usage of FPU inside of an ISR
moved all xtensa specific files into a separated folder
Added task state field inside of TaskSnapshot_t to capture it

newlib libc

move abort to newlib
remove direct dependencies on VFS functions
newlib: provide default implementations for more syscalls
newlib: Added endian.h header file for compatibility (#4784)
newlib: initialize syscall_table_ptr_app in single core mode

LWIP

Added IPV6 stateless address autoconfiguration support
Added config option for SO_LINGER
Added simple SMTP email client
Add LWIP_ASSERT control
Added host name in discover packets
Added to sys_arch_protect() a check that the mutex is created before use if not then creates it (#944)
Added support for IPv6 events from PPP interface
Added support for NAPT functionality
pppos_client: Fix power_down dce immediately after got IP (#4618)
pppos_client: added support for PPPAUTHTYPE_NONE
Wrap lwip/tcp.h header for compatibility (#4637)
Fix the crash caused by socket lock not initialized
Fixed an issue entering an incorrect multicast address will return success
make IPV6 link-local support over PPP configurable (#4782)
esp_netif_ppp: added NETIF_PPP_AUTHTYPE_NONE to esp_netif_auth_type_t (#4639)
esp_netif_ppp: fixed posting ip-event data (#4634)
esp-netif: easier creation for WiFi interfaces with custom parameters (#4611)
esp-netif: fix get/set hostname API to reflect user settings (#4737)
esp-netif: make the IPv6 configurable for PPP netifs
esp-netif: Added API to get the underlying interface name
esp-netif: Fix compilation if ESP_GRATUITOUS_ARP not enabled (#5294)
Fixed assertion "netconn marked closed" (#3842)
esp-netif: set default interface for ppp netif must be called from lwip context
esp-netif: Enable easier configuration of custom DHCP server address
esp-netif-ppp: added support for setting ppp netif up and down
esp_netif: Remove restarting DHCP client and server if it has already been started
esp-netif: added new API to get the type of the IPv6 address
esp-netif: ppp netif to use netif_is_link_up() to update interface state (#5069)
esp_netif: fix default connect handler to check dhcpc return value (#5184)
Fixed the issue that socket can still send data after the station disconnected from WiFi in IPv6 environment
dhcp-server: fixed static analysis warnings
dhcp sever: Make option netmask configurable (#4988)
esp_modem: updated pppos_client modem to use uart with REF_TICK (#4801)
esp_modem: Ensure uart_param_config and uart pins are set before uart_driver_install (#4904)
esp_modem: Fix misuse event_queue_size as pattern_queue_size (#5182)
esp_modem.c: post PPP stop event when requested (#4642)
Fixed the issue of failing to set DHCP timeout during system initialization
Fixed assert when calling tcp_kill_state
Fixed failure to set DHCP timeout during system initialization
Fixed the issue of UDP packets loss in ARP in UDP tx performance testing
Make LWIP TCP rto time configurable
IPv6: fixed the issue that packets exceeding MTU can still be sent and received when IP fragmentation is turned off
Fixed ICMP bug to reply correctly to pings with arbitrary length
esp-netif: Enable easier configuration of custom DHCP server address
Optimization in creating a TCPv6 connection
Fixed potential crash in reapplying for UDP socket when UDP is turned off,sock->select_waiting !=0

mDNS

Allow config mDNS task stack size (#5216)
Limit the GOT_IP6_EVENT to only known network interfaces
Remove mbedtls dependency (#5188)

Provisioning

Use dynamic buffers instead of static memory
Unified Provisioning: Fixed BLE characteristics read response issue when read response length is a multiple of (MTU-1) length
wifi_prov_mgr: Add config options to switch transport and support for custom data
esp_prov: Add support for sending some abstract custom data
BLE: Change service_uuid to non-standard 128-bit UUID
BLE provisioning: Add check for valid ble read offset
Wifi_prov_manager: Fix to ensure Wi-Fi events still received after Connection errors
protocomm_httpd: Restart security session if request is received on a new session

OTA

Added fix in case of URL redirection and a test case of URL redirection (#4780)
Added errno check for WiFi disconnection while performing OTA
Fixed bug where erase size could be one sector too long (#4953)
Added API to write data in a non contiguous manner

HTTP Client

Added helper API to read larger data chunks from HTTP Stream
Added API to get URL from client (#5115)
http_header.c: Add error print in http_header_generate_string if buffer size is less than required size
Fixed error handling in esp_http_client_read and esp_https_ota_perform

HTTP Server

Added support of Mutual Authentication in HTTPs Server (#4184)
Added WebSocket support (#4306)
- Handling WebSocket handshake
- Receive WebSocket packets
- Send WebSocket frames
- Receive WebSocket frame
- Automatic control frame handling
Fixed HTTPD_SSL_CONFIG_DEFAULT doesn't compile on C++ (#4981)
Fixed syntax error in esp_http_server.rst (#5021)
Fixed a bug which could cause issues with LRU purge (#4753)
Updated LRU counter on accepting a new connection (#3851)

mbedTLS

Added ESP certificate bundle feature, X509 certificate management
Added configurable option to redirect TLS buffers to IRAM for ESP32 single core configuration
Added configuration options for EC-JPAKE (#5106)
Added config options for chacha20, poly1305 and chachapoly
Added a config option to enable HKDF
Added dynamic buffer and local resource management to decrease SSL heap cost
Added config options in mbedtls
Added options to mbedtls for hardware acceleration
Updated to mbedtls release v2.16.7
cert bundle: Fix memory leak during cert verification (#4983)
cert_bundle: fixes the "No CA Chain is set" error
Disable mbedtls EC curves if hardware acceleration is selected since the hardware will have to define the curves supported
Don't compile hardware MPI & SHA files if disabled in config

ULP

Fixed ulp external project arguments (#4713)

Bootloader

Removed bootloader_flash_gpio_config () due to its same function of bootloader_flash_dummy_config
Don't print an error message after WDT reset in unicore mode (#4388)
bootloader_support: Fixed bootloader_flash_read alignment error when compiling at -O0 optimization level
bootloader: Force bootloader_image_hdr to be word aligned
bootloader_support: read random from register
bootloader_support: initialize mbedtls_ctr_drbg_context per mbedtls v2.16.5 requirement

ESP-ROM

link newlib nano from ROM only if SPIRAM cache workaround is disabled
Fix esp32.rom.newlib-time.ld should includes all time ROM functions/data (#4925)
Fix broken CONFIG_LEGACY_INCLUDE_COMMON_HEADERS

ESP-TLS

Added API to retrieve sockfd from tls connection
Added connection timeout to esp_tls_conn_new_sync()
Added support for https_server using wolfSSL
Added error flags specific wolfSSL
Added support for PSK, SNI, ALPN using wolfSSL
Added support for DER formatted certificates
Added support for using hardware security module, ESP32-WROOM-32SE
Fixed error captures
Made respective changes to esp_err_to_name.c
Changed argument pointer type to (void *) for esp_crt_bundle_attach
Fixed incorrect error message after handshake fails
Enable TLS renegotiation using explicit API call

TCP Transport

Implement connect timeout (#3791)
Close to return error only for socket error or invalid arguments (#4872)
Updated DNS host name resolution using getaddrinfo for tcp transports (#4510)
Reset state on connection closure for SSL transports (#4598)

Websocket

Fixed opcodes when performing a fragmented send (#4974)
websocket client: the client now aborts the connection if send fails

ESP-MQTT

Added option to configure MQTT task priority (#4947)
Fixed an issue which could result in a race condition and subsequent crash
Change the message printed after MQTT connection failure
Documentation: Makes clear that publish API could block
Added option to configure output buffer size
Set duplicate flag for both qos1 and qos2 (#4787)
Fixed C++ build failing on incorrect event enum conversion
Fixed releasing lock if subscribe/unsubscribe message fails to be created
Fixed receiving longer (websocket) data with standard tcp_transport reads
Fixed possible double free of client config if init fails
Fixed queueing oversized messaged even if not connected
Fixed outbox_destroy() to correctly delete all queued messages
Added set_config to update ssl-transport configuration
Fixed storing timestamps in long-long format
Added runtime selection of mqtt protocol version
Support larger buffers and messages

Storage

NVS: Change all new to new (nothrow)
NVS: Fixed missing implementations for string/blob
NVS: add support for i16, u64, i64 types to NVS partition generation tool
NVS: added nvs support data encodings
NVS: allow to specify custom partition (#5172)
NVS: iterator skipping version 1 blobs
NVS: improved behavior for erasing partitions
SPIFFS: Fixed bugs when CONFIG_SPIFFS_USE_MTIME is not defined
SPIFFS: restore dependency of flash targets on spiffs images (#5066)
NVS Flash: prevented erasing initialized partition (#4755)
spi_flash: fix regression in encrypted flash write (#5467)
spi_flash: added support of MXIC flash chips
spi_flash: fixed the regression of non-quad mode by default chip driver, issues in add_device
spi_flash: Fixed the write performance regression
SDMMC: Fixed the probe issue that forbid sdspi working in highspeed mode
SDMMC: Added check for function parameters before using them (#5000)

VFS

VFS: Check in select() if the UART driver is installed or not
VFS: add option to disable VFS layer, saving some RAM and code size
VFS: supporting semihosting_common handler from OpenOCD
VFS: support vfs uart set line endings with specified uart number

Modbus

freemodbus: fixed long buffer failure
freemodbus: added extern c block into common header for cpp (#5071)

Tools

Added tools support for secure boot v2 for ESP32 ECO3
Added check if idf_tools.py install-python-env is called from a venv
Added proper multi-chip support for idf_size.py
Added option to show differences between MAP files with idf_size.py
Added the functionality of autodetecting the target of MAP files in idf_size.py
Added export and install scripts for fish shell (#4944)
Added --gdbinit argument to gdb, gdbgui, gdbtui
Added Kconfig for enabling 0 length returns from linenoise
ninja: update to 1.10.0
cmake: update to 3.16.4
Updated toolchain to esp-2020r2
esptool_py: retained flash targets when building RAM loadable apps
esptool_py: pass flash mode/frequency/size to elf2image
Updated kconfiglib to 13.7.1
Marked ULP toolchain as not available on 32-bit Linux
idf_tools.py: fix typo in PYVENV_LAUNCHER env variable name
docker: install CMake version provided in tools.json (#4644)
docker: enable ccache by default
tools: work around usbser.sys bug in idf_monitor (#4676)
gen_esp32part: fixed subtype in PartitionTable.find_by_type (#4723)
check_python_dependencies: If overriding requirements.txt path, provide a pip command line
idf_tools.py: fixed install-python-env failure with virtualenv 20.0.0
installer: fix copying IDF to a destination on another drive (#4128)
installer: used bundled idf_tools when installing IDF v3.3.1, IDF v4.0
installer: added PYTHONUNBUFFERED=1 when calling idf_tools.py
tools: bump version of windows tools installer to v2.3
idf_monitor: automatically decode UART core dumps
idf_monitor: fixed gdb issue opening large COM port on Windows
confserver: Standardize and document the handling of hex values
confserver: Always store hex values in sdkconfig with 0x prefix
C++: added experimental C++ component
C++: added ESPException class to the C++ experimental component
C++: make attribute((init_priority(n))) work (#5038)
Force the order of cmake generators
partition_table: output partition table info for partition_table target
partition_table: do not always display partition table contents on build
Updates OpenOCD version to 'v0.10.0-esp32-20200420'
Removed unused toolchain-prefix argument from idf_size.py
Fixed flashing encrypted binaries from IDF Monitor
export.sh: added better detection and checking of IDF_PATH
idf_monitor: support to re-flash with the using port
Make Unicode from subprocess result in the CMake convert script (#5189)
tools: allow alternative spellings of target name (ESP32-S2, ESP32S2)
gdb: Modify PC in case of invalid PC
Fixed spelling in core_ext.py (#5145)
parttool: Fixed crash when retrieving partition info (#5271)
idf.py: prevent reloading duplicate extension paths. Do not load cwd if IDF_EXTRA_ACTIONS_PATH is not set (#5278)
idf.py: replace the "run" method of Task with the magic "call" method (#5279)
Mention ESPPORT and ESPBAUD in idf.py --help (#5461)
export.sh: fix compatibility with dash shell (#5366)

Build System

CMake: Used underlying flash targets for idf.py
Cmake: add subdirectory if exists utility
CMake: now use new component registration function
CMake: add elf dir information
make: Fixed quoting when flashing port is set via sdkconfig file
build: Added CONFIG_APP_PROJECT_VER to set the project version from Kconfig
idf_py: fixed the ESPPORT environment variable type issue
idf.py: added monitor-baud option to monitor command
idf.py: guess IDF_TARGET from sdkconfig if CMakeCache doesn't exist
idf.py: fail and show instructions on IDF_TARGET mismatch
idf.py: added support of debug targets for easier execution of openocd, gdb, gdbui
Fixed idf.py to be able to select a generator for build
confgen.py: Escape special characters for cmake (#4751)
ulp: use quotes when specifying files for embedding ulp binaries
make: fix 'make monitor' target when core dump is not enabled
CMake: Fixed an issue where builds are invoked twice when executing flash targets with idf.py
CMake: show error message on encrypted flash targets without proper config
Cmake: fixed possible whitespace issues
Cmake: Add warnings that convert_to_cmake.py doesn't calculate component requirements
Cmake: fix setting defaults in idf_build_process (#5053)
Fixed passing argument to ULP CMake script
msys2: add package mingw-w64-i686-gcc for installing python packages
ldgen linker script mapping rules order is now deterministic
kconfig: Fix generation of hex outputs for Make & CMake
kconfig: Fix two cases of hex values being handled incorrectly (espressif/vscode-esp-idf-extension#83)
Updated MSYS2 pre-compiled legacy build environment to use Python 3

ESP-COMMON

esp-compiler: add designated init macros to make esp configuration pattern viable under C++

External Libraries

Updated to mbedtls release v2.16.7
cJSON: include only source file objects for cmake build
coap: move mbedTLS config options from component to examples(#5262)

Others

linenoise: move allocations from stack to heap, fix calloc result checking (#5161)
Fixed the broken python lint on Github Action (#5318)

Examples

Added ENC28J60 Example
Added example of ble mesh coexisting with tcp
Added atecc608_ecdsa example (#4432)
softap example: Added channel configuration
spi: add eeprom example
Added Heap Task Tracking example
example: new DAC example of waveform generator controlled by software
NimBLE: Update the documentation link in the examples
ble_mesh: Fixed broken links to examples
ble_mesh: Added BLE mesh sensor model examples
ble_mesh: Add bluedroid and nimble example configurations
ble_mesh: Added BLE mesh vendor models examples
ble_mesh: Update mesh console example
ble_mesh: Added nvs operations for some examples
ble_mesh: Fixed example README & tutorial link error
sdio: updated the host example to support working with a slave without DAT1
Fixed Advanced OTA Example with chunked servers
Simplified console examples
Moved C++ examples to a new cxx folder in examples
Fixed markdown table formatting in examples/peripherals/temp_sensor_esp32s2/README.md (#4609)
Improved ble_spp_server example
Fixed the error macro name and error return in hfp_hf example
Cleaned up sdkconfig.defaults of BLE Mesh examples
Fixed standard NEC IR transmission (#4750)
Updated websocket example to send textual data with esp_websocket_client_send_text() (#4640)
pppos_client: update sdkconfig.defaults
Enabled IPv6 in example common connect for esp32s2
common connect: fixed build error if ipv6 disabled
common connect: add support for getting multiple IPv6 addresses
Fixed typo in i2ctool example README
provisioning_examples: Move older examples to legacy/ folder
Restructured wifi_provisioning example
Fixed http_perform_as_stream_reader example
esp_http_client: Added example to demonstrate use of low level APIs for GET and POST requests
Fixed broken http2_request example
socket-example: IPv6 related update for examples to set correct scoped id
socket-example: Add tcp client example for multiple interfaces
I2S: Fixed sine wave sample calculation incorrect issue in I2S example
Updated esp event examples using new event register API
socket examples: Fixed udp_client build error (#5014)
Fixed format string in websocket example (#5052)
http-server-example: correction of regex waiting to acquire IP address
Fix instance names for event handler unregistering in WiFi station example (#5064)
uart_echo_readme: Remove duplicate commands and invalid serial port information
Updated HID examples to comply with the new requirements
Fixed links to example directories for fast_scan and scan (#5186)
Fix usage example in xSemaphoreCreateBinaryStatic (#5272)
esp_http_client_example.c: Added note regarding use of URL and configuration parameters
Fixed flake8 warning for esp-cryptoauthlib submodule
ble_hid_device: fix build if building with c++ (#5191)
RMT: Fixed check issue in ir_builder_rmt_nec.c and removed the wait_tx_done for ir_protocols_main.c (#4750)

Documentation

Documentation is now built separately for ESP32 & ESP32-S2
Added Chinese translation to LEDC
Added new top-level docs builder that builds docs for a single chip
Added API guide page about IDF Tools
Added extension that replaces generic target variable with idf_target
Added external RAM note link to Chinese translation
Added a link to Chinese translation for power_management_esp32
Added note that the idf target formatting filters don't work on "included" documents
Added Chinese translation for esp-ble-mesh-faq
Added a short user guide for how to write multi target docs
Added docs for secure boot v2 ESP32 ECO3
Added multi target include dir support
Added User Guide for ESP32-DevKitS-R
Added Chinese translation for ESP-WIFI-MESH document under api guide
Added Chinese translation for ota tool and partition tool
Added Chinese translation for linker script generation
Added Ethernet API reference
Added exact git version & target SoC to feedback form parameters
Added warnings about using JTAG debugging with hardware security features
Added configuration information about INT & Task WDTs
Added Chinese translation for modules-and-boards
Added alloc failed hook documentation
Added new section about using ESP-IDF with PlatformIO (#5132)
Added peripheral_types.h as API reference for peripheral docs
Added generation of tags from sdkconfig and x_caps.h headers
Added link back to ESP-ADF documentation in ESP-LyraT-8311A user guide
Added another case and recommendation to use Python 3 instead of Python 2
Added the support of building a subset of the documentation with build_docs
Added peripheral_types.h as API reference for peripheral docs
Added a note about ESP-IDF FreeRTOS version
Added description to Getting started guides of possible issues preventing Development boards from entering Firmware Download mode automatically while trying to flash the boards
Make docs build Python 3 compatible
Small changes for C++ code style
Manage parallel sphinx-build runs with optional parallel jobs within them
Replace all TRM urls will generic template variable and remove duplicate sections
Temporarily mark RF calibration chapter as ESP32 only
documenting-code: Add a couple of follow up notes on top of last commit
README: Drop the RTD docs status badge, add a note about docs not updating for a period
Updated chip features in Getting Started documentation
Updated documentation build system to use sphinx_idf_theme pip package
Provided Digital Signature documentation for ESP32-S2
Fixed broken links in README

Obtaining v4.2-beta1

For full installation instructions, see the ESP-IDF Programming Guide.

The source files attached to this release will not work due to our use of git submodules. Use one of the following methods instead:

Using git

To get this release, use the following commands:

git clone -b v4.2-beta1 --recursive https://github.com/espressif/esp-idf.git esp-idf-v4.2-beta1
cd esp-idf-v4.2-beta1/

This is the recommended way of obtaining v4.2-beta1 of ESP-IDF.

Download an archive with submodules included

Attached to this release is an esp-idf-v4.2-beta1.zip archive. It includes .git directory and all the submodules, so can be used out of the box. This archive is provided for users who have connectivity issues preventing them from cloning from GitHub.

This archive can also be downloaded from Espressif's download server:
https://dl.espressif.com/github_assets/espressif/esp-idf/releases/download/v4.2-beta1/esp-idf-v4.2-beta1.zip

espressif/esp-idf v4.2-beta1 ESP-IDF Pre-release v4.2-beta1 on GitHub

Major New Features

Known Issues

Bluetooth

Classic Bluetooth

Controller

Bluedroid

Bluetooth Low Energy

Controller

Bluedroid

Blufi

NimBLE

ESP-BLE-Mesh

Wi-Fi Coexistence

Wi-Fi

ESP-WIFI-MESH

ESP-NOW

Smartconfig

Ethernet

Security

Peripheral Drivers

Core System

Debugging

FreeRTOS

newlib libc

LWIP

mDNS

Provisioning

OTA

HTTP Client

HTTP Server

mbedTLS

ULP

Bootloader

ESP-ROM

ESP-TLS

TCP Transport

Websocket

ESP-MQTT

Storage

VFS

Modbus

Tools

Build System

ESP-COMMON

External Libraries

Others

Examples

Documentation

Obtaining v4.2-beta1

Using git

Download an archive with submodules included

espressif/esp-idf v4.2-beta1
ESP-IDF Pre-release v4.2-beta1

on GitHub