Nrfutil

Bugfixes/improvements
- Add data_length_update to BLE DFU (293)
- Fix the range of supported Python versions (292)
- Fix invalid c syntax in key source display (290)

Features
* Added Python 3 support (3.6, 3.7 and 3.8), removed Python 2 support (250, 257, 267, 282)

Bugfixes/improvements
* Updated dependency requirements (259, 262, 283)
* Zigbee updates (225, 226, 227, 230, 240)
* Thread updates (223)
* Update CLI error reporting (258)
* Updated SoftDevice ID list (242)
* Added check for application version string format (269)

Features
* Added Python 3 support and removed Python 2 support (250, 257, 267)
Python 3.7 is the minimum required version.

Bugfixes/improvements
* Updated dependency requirements (259, 262)
* Zigbee updates (225, 226, 227, 230, 240)
* Thread updates (223)
* Update CLI error reporting (258)
* Updated SoftDevice ID list (242)
* Added check for application version string format (269)

This major release marks the migration to Python 3.7, removing Python 2 support. This release also pulls in the latest of dependencies.

Dependency version constraints have intentionally been removed from setup.py to give projects pulling in nrfutil leeway and responsibility of ensuring compatibility and freezing dependencies. Unfortunately this means that installing nrfutil standalone from the egg may break anytime and require manually fixing dependencies. A new file `requirements-frozen.txt` has been added which freezes the dependency environment from time of testing and should always work.

Features
* Added a masterkey option for thread dfu (182)

Bugfixes/improvements
* Fixed loading of libusb library (215)
* DFU trigger will attempt to resolve bootloader port even without reciving a libusb disconnection event (221)
* Fixed error with uploading images with size being multiple of 64 bytes (223)

Note
* antlib module needs to be installed before doing ant DFU feature (218)

Features
* Revert "Placing public key in RAM if Oberon crypto backend is used." (150)
* Remove required-flag from some options (184)
* Tone down warning about overwriting nRF DFU settings backup page (185)
* Perform address argument validation (187)
* Addition of ANT transport for DFU (189)
* Implement DFU trigger interface (190 , 193 196)
* Added libusb1 binaries for Windows and MacOS.
* Implemented device lister.
* `-snr` (serial number) can be provided instead of `-p` (port) for `nrfutil dfu [usb-]serial`.
* ATT MTU can be changed when performing `dfu ble` using `-mtu` argument (197)
* Add options to configure serial update timeouts (199)
* Change uart connect timeout (201)
* Added EUI64 randomization to the Zigbee OTA DFU (202, 204)

Security
* Update required version of pyyaml (205)
* Add version specifiers to pip requirements (192)