Support for Arduino IDE 2.0.4 and later is available by adding this package index URL in File > Preferences.
https://www.pjrc.com/teensy/package_teensy_index.json
Support for Arduino IDE 1.8.x using installers, available here:
https://www.pjrc.com/teensy/td_download.html
Changes since Teensyduino 1.61:
Update gcc toolchain from 11.3 to 15.2
Fix Wire library compile error with new toolchain
Add Windows 64 bit toolchain for Arduino 2.3.x
Add Linux ARM 32 and 64 bit toolchains
Fix MacOS toolchains for Teensy 2
Update all toolchains - remove unused stuff to reduce download size
Fix SPI compile time init on Teensy 4
Update teensy_size, print white text in Arduino 2.3.x
Fix compiler warnings in MANY libraries
Add Optimize Faster with Nano Libc on Teensy 4
Disable maybe uninitialized warnings
Reduce C++ STL bloat with empty __verbose_terminate_handler (thanks jmarsh)
Fix compiler warning in USB_MIDI InputRead example
Fix compiler warnings in ssd1351 library
Fix lag between compile and upload on Arduino IDE 2.3.x when serial monitor open
Workaround for Serial+MTP serial monitor reconnect after upload on Windows