CircuitPython 6.0.0 Release Candidate 0 released!

From the GitHub release page:

This is the first release candidate of CircuitPython 6.0.0. We don’t know of any stability issues overall. See port status below for more stability detail. If you find any issues with it, please file an issue. If no issues are found within a week or so, we’ll release this version as stable.

Download from

Downloads are available from The site makes it easy to select the correct file and language for your board. The downloads page is here. Downloads are no longer available from the GitHub release pages because of the large number of files for each release.


To install follow the instructions in our new 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).

Port status

CircuitPython has a number of "ports" that are the core implementation for a variety of microcontroller families. Stability varies on a per-port basis. As of this release, atmel-samd, nrf, and stm for the F4 family are stable. cxd56, esp32s2, and stm for other chip families are being actively improved but may be missing functionality and have bugs. litex and mimxrt10xx are in an alpha state and will have bugs and missing functionality.

New features and improvements since 6.0.0 Beta 2

Fixes and enhancements

  • Enable async and await keywords and adds __await__ support. Thanks to @warriorofwire
  • Add ESP32-S2 analogio support. Thanks to @hierophect
  • Add canio support to the STM32F405 boards. Thanks to @jepler
  • The HCI version of _bleio is available on many non-nRF boards (nRF is not included since it already has native BLE). Thanks to @dhalbert
  • Fix display memory bugs. Thanks to @jepler and @cwalther

Board- and port-specific changes

  • Add ability to set hostname to ESP32-S2. Thanks to @askpatrickw, @microdev1, @unexpectedmaker
  • Fix STM sleep timing. Thanks to @tannewt, @FoamyGuy, @DavePutz
  • Fix STM time keeping that lead to unnecessary I2C timeouts. Thanks to @tannewt, @jepler, @FoamyGuy, @eLEcTRiCZiTy, @mdroberts1243, @DavePutz, @hierophect
  • Fix SAMD21 auto-reload issue. Thanks to @tannewt
  • Fix SAMD21 timing issue causing flickering on the pew. Thanks to @tannewt, @deshipu, @cwalther, @DavePutz, @jepler
  • Fix RGB Matrix crash when brightness is set to zero. Thanks to @jepler
  • Rework the flash config for iMX RT boards and enable the DCache (but disable caching for the OCRAM.) Thanks to @tannewt
  • Update to the latest ESP-IDF from Espressif. Thanks to @hierophect


  • Numerous translation additions and improvements. Thanks:
    • @wtuemura (Brazilian Portugese)
    • @hexthat (Chinese Pinyin)
    • @Edrig (French)
    • @oonid (Indonesian)
    • @dherrada (Spanish)
    • @bergdahl (Swedish)

Full commit log is here.

Breaking changes since 5.x

  • i2cslave is now i2cperipheral and the class in it is changed as well.
  • The stop kwarg has been removed from I2C.writeto(). If no stop is desired, then use writeto_then_readfrom.
  • The default speed of busio.I2C and board.I2C is now 100khz, not 400khz as before. Use busio.I2C to set the speed explicitly. #3471 Thanks @caternuson, @ladyada, @hierophect and @tannewt
  • _bleio.ConnectionError has be removed. Code will now raise the native ConnectionError instead.

New boards since 6.0.0 Beta 2

Known issues

  • Nothing major.
  • See for other issues.


Thank you to all who used, tested, and contributed since 6.0.0 Beta 2, including @askpatrickw, @bergdahl, @bh34n, @caternuson, @cwalther, @DavePutz, @deshipu, @dhalbert, @dherrada, @ecasadod, @Edrig, @eLEcTRiCZiTy, @FoamyGuy, @hexthat, @hierophect, @jepler, @ladyada, @mdroberts1243, @microdev1, @oonid, @tannewt, @unexpectedmaker, @warriorofwire, @wtuemura and many more on Discord. Join us on the Discord chat to collaborate.


Documentation is available in

This release is based on MicroPython 1.9.4 @25ae98f. Support upstream MicroPython by purchasing a PyBoard (from Adafruit here) or sponsoring MicroPython on GitHub.


One important feature of CircuitPython is translated control and error messages. With the help of fellow open source project Weblate, we’re making it even easier to add or improve translations. Sign in with an existing account such as Github, Google or Facebook and start contributing through a simple web interface. No forks or pull requests needed!


Check out this guide for info on common problems with CircuitPython. If you are still having issues, then post to the Adafruit Support Forums and join Discord.


Builds are no longer stored as assets on this release page, because there are too many of them. Please see the Download from section above.

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