Here is a third beta test for Teensyduino 1.49.
EDIT: links removed, please use 1.49-beta5
Changes since Teensyduino 1.49-beta2
Fix delay() and micros() on Teensy 4.0 at 24 MHz
Fix USB touchscreen
Fix serial receive at very high baud rates on Teensy 4.0
Fix MIDI+Serial on Teensy 4.0
Fix USB Keyboard sending "garbage" in long strings on Teensy 4.0
Fix analogWrite for values >= 2^res on certain Teensy 4.0 pins
Wire only clear FIFO with bus is idle on Teensy 4.0 (KurtE)
Wire use open drain pin config on Teensy 4.0
Update ST7735_t3 library
SPI optimize usingInterrupt() on Teensy 4.0 (FrankB)
SPI allow faster clock speeds on Teensy 4.0 (KurtE)
Fix daylight saving time issue with automatic RTC set on Teensy 4.0
Add Makefile for Teensy 4.0
Add main.cpp for Teensy 4.0 (KurtE)
Fix compiler warnings on Teensy 2.0
EDIT: links removed, please use 1.49-beta5
Changes since Teensyduino 1.49-beta2
Fix delay() and micros() on Teensy 4.0 at 24 MHz
Fix USB touchscreen
Fix serial receive at very high baud rates on Teensy 4.0
Fix MIDI+Serial on Teensy 4.0
Fix USB Keyboard sending "garbage" in long strings on Teensy 4.0
Fix analogWrite for values >= 2^res on certain Teensy 4.0 pins
Wire only clear FIFO with bus is idle on Teensy 4.0 (KurtE)
Wire use open drain pin config on Teensy 4.0
Update ST7735_t3 library
SPI optimize usingInterrupt() on Teensy 4.0 (FrankB)
SPI allow faster clock speeds on Teensy 4.0 (KurtE)
Fix daylight saving time issue with automatic RTC set on Teensy 4.0
Add Makefile for Teensy 4.0
Add main.cpp for Teensy 4.0 (KurtE)
Fix compiler warnings on Teensy 2.0