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CircuitPython 5.0.0 Release Candidate 1 Released!
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Please be positive and constructive with your questions and comments.

CircuitPython 5.0.0 Release Candidate 1 Released!

by danhalbert on Sun Mar 01, 2020 5:44 pm

This is a 5.0.0 Release Candidate -- please test

This is release 5.0.0-rc.1 (Release candidate 1). If this release does not have show-stopper issues, it will be re-released as 5.0.0, the first 5.x.x stable release.

If you find a bug please check the current known issues and file an issue if something isn't already known.


5.0.0 is the latest major revision of CircuitPython. It features many improvements and enhancements to displayio, including grayscale OLED and e-paper displays, extensive additions and improvements to BLE support, support for the STM32F4, iMX RT10xx and Sony Spresense microcontroller families, and PWM audio support.

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).

New Features, Updates, and Fixes Since 5.0.0-rc.0


  • Fix I2C clock speed on i.MX boards. Thanks @mubes.
  • Freeze adafruit_requests and adafruit_esp32spi libraries into mimxrt1011 builds to save RAM. Thanks @arturo182.
Other board-specific fixes

  • Arduino M0 boards now have both .bin and .uf2 downloads available. Thanks @dhalbert, and thanks to @fgallaire for pointing out the issue.
Build infrastructure

  • Release download links available at now point to AWS S3 instead of to GitHub release assets. Thanks @dhalbert, @jwcooper, and @sommersoft.
New Boards

Find downloads for all boards, including these, at

New Since 5.0.0-rc.0


Breaking Changes and Deprecations from 4.x

  • 5.0.0 improves our internal filesystem definitions and may overwrite your existing files so make sure to back them up before updating!
  • The bleio module has been renamed to _bleio to indicate that it is meant to be used only for writing BLE libraries, and that its API may change between CircuitPython minor versions. There are many incompatible changes in _bleio since 4.0.0. Please use the latest adafruit_ble library for end-user BLE programming.
  • The displayio refresh API has been revamped to be simpler. wait_for_frame and refresh_soon have been removed. In both 4.x and 5.x, auto refresh will automatically refresh the display so they can be removed. The new auto_refresh property and refresh() function can be used to control when the screen refreshes and at a specific rate.
  • Moved audioio.Mixer to audiomixer.Mixer, which is only available on M4s. Moved audioio.RawSample, and audioio.WaveFile to the new module audiocore. However, for backwards compatibility, they are still available in audioio. They will be removed from audioio in 6.0.0. Thanks @jepler.
  • Added I2C.writeto_then_readfrom(). Deprecate stop= arg which will be removed in 6.x. Use I2C.writeto_then_readfrom() instead.
  • Removed re from CircuitPlayground Express Display build.
  • Removed gamepad from CircuitPlayground Express Crickit build.
Known Issues

  • displayio operations that read from an SD card (e.g., OnDiskBitmap) will interfere with other SD card operations and can cause lockup. To work around this problem, do not read or write files on the SD while the display is updating, and [cur]vice versa[/cur].
  • See for other issues.@

Thank you to all who used, tested, contributed, helped out, and participated on GitHub and/or Discord, including @arturo182, @bmeisels, @DavePutz, @dhalbert, @fgallaire, @hierophect, @jamesbowman, @jepler, @ladyada, @lgnashold, @maholli, @makermelissa, @mubes, @neubauek, @pdp7, @rhooper, @tannewt, @ATMakersBill, @AndrewTribble, @Anne B, @Antonio, @CGrover, @CarlFK, @Curt Olson, @Dar, @DaveP, @DavidGlaude, @DudeImOnly6, @Duewester, @KingerNorth, @SouthernDragon, @TG-Techie, @ThomasAtBBTF, @adafruit, @anecdata, @brentru, @cater, @charlesburnaford, @codeNSolder, @deshipu, @dherrada, @diegoMini+, @ednl, @foamyguy, @geekguy, @graham, @hexthat, @jasonp, @jerryn, @kattni, @kjw, @madbodger, @marius_450, @mscosti, @ntoll, @siddacious, @sommersoft, @stargirl, @timvictor, @v923z and surely more we have missed. Join us on the Discord chat to collaborate.


Documentation is available in

Here are all the changes since 5.0.0-rc.0.

This release is based on MicroPython 1.9.4 @25ae98f. Support upstream MicroPython by purchasing [url=[project]/store]a[/project] PyBoard[/url] (from Adafruit here).


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.

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Please be positive and constructive with your questions and comments.