CircuitPython 9.0.0 Release Candidate 0
Pre-releaseThis is CircuitPython 9.0.0-rc.0, a release candidate for 9.0.0 final. This release is believed to be stable, and is meant for testing before the final release of 9.0.0.
WARNING for nRF52 boards only: If your board has an nRF52 UF2 bootloader whose version is before 0.6.1, you will not be able to load CircuitPython 8.2.0 and later, due to increased size of the firmware. See these instructions for updating your bootloader.
Notable changes to 9.0.0 since 8.x.x
Incompatibility warnings
- New storage management. See Internal below about possible new memory errors with existing programs.
 - Filesystems such as SD cards must now be mounted on an existing directory as a mount point. See Storage below.
 - Incompatible change in 
socketbehavior: Sockets must be explictly made reusable. See Networking below. displayio.*Display.show()has been removed. Use*Display.root_group =instead.I2CPeripheralis nowI2CTarget.
Audio
- Add 
synthio.Note.loop_startand.loop_endproperties. - Add 
synthio.Synthesizer.note_state. - Add I2S MCLK support on Espressif.
 - Allow signed amplitude in 
synthio. 
Built-in modules
- Add 
OrderedDict.move_to_end(). - Add 
warningsmodule, similar to what is in CPython. - Add 
locale.getlocale(). - Add 
codeop.compile_command(). - Remove 8.x.x deprecations: 
displayio.*.show(),I2CPeripheralrenamed toI2CTarget. 
Graphics
- Reorganize and split 
displayio. 8.x.x naming structure is available in 9.x.x, but will be removed in 10.0.0. - Add 
jpegioJPEG decoder support. - Add 
bitmapfilterimage manipulation. 
Internal
- New split-heap internal dynamic storage mechanism. Some CircuitPython programs may fail with 
MemoryError. If you encounter programs that work in 8.x.x but getMemoryErrorexceptions, consider filing an issue with details. - Merge updates from MicroPython v1.19.1, v1.20.0, and v1.21.0.
 - Espressif: update to ESP-IDF v5.1.3.
 
Networking
- Allow specifying protocol for raw sockets.
 - Add mDNS TXT record support.
 - Make SD cards available over web workflow.
 - Allow fetching of associated stations in access-point mode.
 - Incompatible change: Require explicit socket port reuse. Use 
socket.setsockopt(pool.SOL_SOCKET, pool.SO_REUSEADDR, 1), as in CPython. 
Python interpreter
- Use terser error messages on small builds.
 
Storage
- CIRCUITPY drives now mount on Android.
 - Increased file capacity on CIRCUITPY drives <= 128kB.
 - Incompatible change: Require filesystem mounts to be on existing directories. Create 
/sdin fresh filesystems to provide a mount point. 
Supervisor
- Add 
repl.py, which runs just before the REPL starts up. 
USB
- Video device ("Webcam", UVC) support.
 - HID can wake up sleeping host computer.
 - Further USB host support, on i.MX and RP2040.
 - Allow setting USB HID interface name.
 
Download from circuitpython.org
Firmware downloads are available from the downloads page on circuitpython.org. The site makes it easy to select the correct file and language for your board.
Installation
To install follow the instructions in the Welcome to CircuitPython! guide. To install the latest libraries, see this page in that guide.
Try the latest version of the Mu editor for creating and editing your CircuitPython programs and for easy access to the CircuitPython serial connection (the REPL).
Documentation
Documentation is available in readthedocs.io.
Port status
CircuitPython has a number of "ports" that are the core implementations for different microcontroller families. Stability varies on a per-port basis. As of this release, these ports are consider stable (but see Known Issues below):
atmel-samd: Microchip SAMD21, SAMx5xcxd56: Sony Spresenseespressif: Espressif ESP32, ESP32-S2, ESP32-S3, ESP32-C3nrf: Nordic nRF52840, nRF52833raspberrypi: Raspberry Pi RP2040stm: ST STM32F4 chip family
These ports are considered alpha and will have bugs and missing functionality:
broadcom: Raspberry Pi boards such as RPi 4, RPi Zero 2Wlitex: fomumimxrt10xx: NXP i.MX RT10xxxsilabs: Silicon Labs MG24 familystm: ST non-STM32F4 chip families
Changes since 9.0.0-beta.2
Fixes and enhancements
- Update frozen libraries. #9019. Thanks @dhalbert.
 - Fix corrupted BLE ScanEntry objects. #9014. Thanks @dhalbert.
 - Setting the 
WatchdogTimertimeout will reset the watchdog interval. #9012. Thanks @tannewt. - Improve 
RGBMatrixreliability. #9008. Thanks @tannewt. - Fix 
ETIMEDOUTexceptions inssl. #9006. Thanks @jepler. - Postpone web workflow request if SPI bus is locked. #9005. Thanks @jepler.
 - Fix USB Host HID. #8999. Thanks @hathach.
 - Allow web workflow to write to CIRCUITPY when connected to USB. #8994. Thanks @tannewt.
 - Disable 
warningsduring REPL autocomplete. #8993. Thanks @tannewt. - Allow setting USB HID interface name. #8989. Thanks @MariuszCwikla.
 - Include language code in USB Host string descriptors. #8976. Thanks @tannewt.
 - Use finalizer to properly clean up 
PWMOutobjects, including those used by other objects. #8966. Thanks @tannewt. - Freeze new 
adafruit_connection_managerlibrary on appropriate boards. #8963. Thanks @justmobilize. - Fix 
ssl.SSLSocket.bind()error checking. #8962. Thanks @tannewt. - Allow fetching of associated stations in access-point mode. #8820. Thanks @romkey.
 
Port and board-specific changes
Broadcom
Espressif
- Update ESP-IDF to v5.1.3. #9008. Thanks @tannewt.
 - Fix 
WatchdogTimerunits. #9012. Thanks @tannewt. - Use a finalizer to clean up 
espcameraobjects. #8990. Thanks @dhalbert. 
i.MX
nRF
RP2040
SAMx
SiLabs
Spresense
STM
Individual boards
- Adafruit QT Py M0 Haxpress: allow W25Q32FV flash chip. #9011. Thanks @guutz.
 - M5Stack Atom S3: fix display colors. #8998. Thanks @jins-tkomoda.
 - PewPew LCD: update board to v4.1. #8959. Thanks @deshipu.
 
Documentation changes
Build and infrastructure changes
- Update 
tlsflibrary to allow allocating just-freed region. #9004. Thanks @tannewt. - Update 
tools/convert_release_notes.pyto usemistunev3. #8955. Thanks @dhalbert. 
Translation additions and improvements
New boards since 9.0.0-beta.2
- Adafruit ItsyBitsy ESP32. #8953. Thanks @BlitzCityDIY.
 - Adafruit SHT4x Trinkey M0. #9007. Thanks @ladyada.
 - M5Stack Cardputer. #8816. Thanks @jamesjnadeau and @FoamyGuy.
 - senseBox MCU-S2 ESP32S2. #8997, #8965. Thanks @mariopesch.
 
Known issues
- See https://github.com/adafruit/circuitpython/issues for other issues, including issues still to be addressed for:
 
Thanks
Thank you to all who used, tested, and contributed since 9.0.0-beta.2, including the contributors above, and many others on GitHub and Discord. Join us on the Discord chat to collaborate.