From the GitHub release page:

This is CircuitPython 9.0.0-alpha.6, an alpha release for 9.0.0. It has significant known bugs, and will have further additions and fixes before the final release of 9.0.0.

NOTE: CircuitPython 9.0.0-alpha.4 and later use a new internal dynamic storage mechanism (“split heap”), which is being tuned. You may find that some CircuitPython programs fail with MemoryError. If you encounter programs that work in 8.x.x but get MemoryError exceptions, consider filing an issue with details.

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

• New split-heap internal dynamic storage mechanism.
• Merge updates from MicroPython v1.19.1, v1.20.0, and v1.21.0.
• Espressif: update to ESP-IDF v5.1.2.
• Reorganize and split displayio. 8.x.x naming structure is available in 9.x.x, but will be removed in 10.0.0.
• CIRCUITPY drives now mount on Android.
• Increased file capacity on CIRCUITPY drives <= 128kB.
• Further USB host support, on i.MX and RP2040.
• Remove 8.x.x deprecations: displayio.*.show(), I2CPeripheral renamed to I2CTarget.
• Add jpegio JPEG decoder support.
• Add repl.py, which runs just before the REPL starts up.
• Add OrderedDict.move_to_end().
• Add synthio.Synthesizer.note_state.
• Add warnings module, similar to what is in CPython.
• Add locale.getlocale().
• Add I2S MCLK support on Espressif.
• Add mDNS TXT record support.
• Add synthio.Note .loop_start and .loop_end properties.
• Allow signed amplitude in synthio.

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, SAMx5x
• cxd56: Sony Spresense
• espressif: Espressif ESP32, ESP32-S2, ESP32-S3, ESP32-C3
• nrf: Nordic nRF52840, nRF52833
• raspberrypi: Raspberry Pi RP2040
• stm: 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 2W
• litex: fomu
• mimxrt10xx: NXP i.MX RT10xxx
• silabs: Silicon Labs MG24 family
• stm: ST non-STM32F4 chip families

Changes since 9.0.0-alpha.5

Fixes and enhancements

• Update frozen libraries. #8717. Thanks @dhalbert.
• Remove same-line comments in mpconfigboard.mk that interfered with settings checks. #8702, #8669. Thanks @dhalbert.
• dotclockframebuffer: round up internal size to multiple of 16 pixels. #8698. Thanks @jepler.
• Add jpegio JPEG decoder support. #8696. Thanks @jepler.
• Enable builts.compile() for all boards. #8687. Thanks @bill88t.
• Process input during websocket operation. #8668. Thanks @tannewt.
• Improve web workflow error handling. #8667. Thanks @tannewt.
• Allow signed amplitude in synthio. #8642. Thanks @jepler.
• Add synthio.Note .loop_start and .loop_end properties. #8629. Thanks @dcooperdalrymple.
• Fix signature for SSLContext.load_verify_locations. #8624. Thanks @dhalbert.
• Add W25Q16JVxQ as alternative flash chip for a number of boards. #8622, #8621. Thanks @dhalbert.

Port and board-specific changes

Broadcom

Espressif

• Fix operation as a simple BLE Central on ESP32-S3. #8645. Thanks @dhalbert.
• Fix IO32 pin AnalogIn. #8622, #8607. Thanks @dhalbert.

i.MX

nRF

RP2040

• Use DMA for PIO when transfer size exceeds FIFO size. #8702, #8700. Thanks @dhalbert.
• Add wifi.stop_ap(). #8622, #8590. Thanks @eightycc.

SAMx

SiLabs

Spresense

STM

Individual boards

• Adafruit HalloWing M0: Add support for 2MB flash chip shipped by mistake on a few boards. #8702, #8669, #8646. Thanks @dhalbert and @jepler.
• Arduino Nano ESP32-S3: Correct USB PID. #8702, #8634. Thanks @dhalbert.
• MakerFabs TFT7: Updates. #8644, #8625. Thanks @RetiredWizard.

Documentation changes

• Document that time monotonic values are only guaranteed to be monotonic per VM instantiation. #8685. Thanks @jepler.

Build and infrastructure changes

• Document decompress_vstr() assumption. #8666. Thanks @jepler.
• Unset D_FORTIFY_SOURCE globally. #8663. Thanks @jepler.
• Share UTF-8 conversion code to save flash. #8655. Thanks @jepler.
• Add branch and PR number to uploaded build filenames (needs more work). #8648. Thanks @dhalbert.
• Fix build error when frozen modules are updated. #8633. Thanks @jepler.
• Fix git version for unified submodule cloning. #8620. Thanks @dhalbert.

Translation additions and improvements

• Thanks for translations:
  • @bill88t (Greek)
  • ChaeYeon Han (Korean)
  • @deepserket (Italian)
  • gfbdrgng (Russian)
  • @hexthat (Chinese – Pinyin)
  • @jessyjones (French)
  • @wtuemura (Portugese – Brazil)
• Do not offer strings contain only %-escapes for translation. #8640. Thanks @jepler.
• Improve synthetic.pot mechanism for strings that do not need translation. #8619, #8617. Thanks @jepler.

New or removed boards since 9.0.0-alpha.5

• Adafruit ESP32-S2 Camera: Removed; never released. #8671. Thanks @dhalbert.
• Breadstick Innovations Raspberry Breadstick. #8636. Thanks @mrangen.
• Cytron Maker Zero SAMD21: Removed; never released. #8689. Thanks @noqman (@CytronTechnologies).
• Cytron Maker UNO RP2040. #8649. Thanks @noqman (@CytronTechnologies).
• DFRobot FireBeetle 2 ESP32-S3. #8623. Thanks @bill88t.
• Facts Engineering P1AM-200. #8665. Thanks @AdamCummick.
• Flipper Zero Wi-Fi Dev. #8673. Thanks @maewolfsky.
• PCTEL WSC-1450. #8656. Thanks @hendriclinden.
• Unexpected Maker TinyC6. #8626. Thanks @UnexpectedMaker.
• WisdPi Tiny RP2040. #8670. Thanks @wisdpi.
• WisdPi Ardu2040M. #8670. Thanks @wisdpi.

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-alpha.5, including the contributors above, and many others on GitHub and Discord. Join us on the Discord chat to collaborate.

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• Source: https://blog.adafruit.com/2023/12/12/circuitpython-9-0-0-alpha-6-released/