IDE

• Fix command line: works again with relative paths (regression)
• Fix command line: "--save-prefs" works again (regression)
• AVR toolchain has been updated with a tentative fix for the ld-returned-5-exit-status bug
• Update arduino-builder to 1.3.25
  • avoid name clashing for libraries
  • cache core archives to speedup compilation consistently
• Allow BoardManager to fetch FreeBSD tools (thanks @kevans91)
• Serial monitor: the input string box is automatically focused when window is selected
• Serial monitor: now can not be opened during upload
• Serial monitor: now properly decodes UTF8 characters (thanks @aknrdureegaesr)
• Serial monitor: added 500k, 1M and 2M baudrates (thanks @dsstutts)
• Updated RSyntaxTextArea to 2.6.1 (textarea component)
• Updated jmdsn (mDNS discovery)
• Allow plugins to attach a listener to compile progress (thanks @tomneutens)

Core

• Add Atmel-ICE and JTAGICE3 programmers for AVR chips (thanks @matthijskooijman)
• AVR: Set unused bits of extended fuse to 1, should remove some avrdude warning during burn bootloader (thanks @descampsa)
• AVR: USB: send ZLP when needed (allows full 64 bytes packets)
• AVR: USB: use IAD descriptors instead than Generic (thanks @cuitoldfish)

Other

• SAM platform source code has been moved to its own repository (https://github.com/arduino/ArduinoCore-sam) - all PRs and issues have been moved as well
• Update Wifi101 Firmware Updater plugin