Teensyduino 1.56 has been released
https://www.pjrc.com/teensy/td_download.html
Quick summary: 1.56 brings support for Arduino 1.8.19 and many fixes and improvements. Teensy 4.0, 4.1, MicroMod get a bootloader update which allows LittleFS_Program filesystem to persist across code uploads.
Changes since 1.56-beta6:
SD & LittleFS listfiles PrintTime check valid month
Fix Print:rintf to call va_end (Shawn Silverman)
SD getModifyTime getCreateTime check 0 from SdFat (KurtE)
Complete list of changes since 1.55:
Support for Arduino 1.8.19
Fix serial monitor stall on Windows
Fix upload failure to locked Teensy 4 if button pressed
FS.h support file create and modify time
SD support file create and modify time
SD automatically uses RTC
LittleFS support file create and modify time
LittleFS automatically uses RTC
Add makeTime, breakTime, DateTimeFields
Fix serial monitor regression with MTP on Linux
Fix digitalPinHasPWM for higher pin numbers on Teensy 4
MTP configure event endpoint on Teensy 4
Add FS format() and mediaPresent()
Add String compatibility to FS,SD,LittleFS,etc
Add LittleFS format() (mjs513)
Add SD format() and mediaPresent()
Update SdFat to version 2.1.0 and enable UTF8 filenames
Edit SdFat examples to compile on Teensy 3 & 4
Audio fix PT8211 when no audio data input (Frank B)
Audio i2s2 slave mode (alex6679)
Update FastCRC (Frank B)
USBHost_t36 HID support 1000 Hz update (Kurt E)
USBHost_t36 Keyboard forward API and example (Kurt E)
Reduce wasted memory during linking (Frank B)
Fix MTP detection on Linux
Fix serial monitor on Linux with MTP
Fix rare serial monitor stall on Windows
Fix rare Null Pointer Exception when closing serial monitor
Teensy Loader updates Teensy 4.0, 4.1, MicroMod to bootloader 1.07
Improve SD.mediaPresent()
Fix SD compile error on Teensy LC
Show helpful error if original SdFat used
Fix SdFat example compile errors, FsFile & SD_FAT_TYPE
Delete SdFat examples not needed for Teensy
Improve SdFat format speed with SHARED_SPI
Improve SdFat free cluster count speed with SHARED_SPI
Add SdFat restart(), to reinitialize hardware & card
SdFat FAT16/32 format use existing buffer (Kurt E)
SdFat support for GPT partitions (Kurt E)
SdFat fix use of USE_SIMPLE_LITTLE_ENDIAN
SdFat fix exfat corruption when using timestamps (Kurt E)
Wire use inline functions for AVR
Wire increase buffer size on Teensy 3 & 4
Wire fix ambiguous requestFrom with bool
FS use block write (Kurt E)
Fix IMXRT_DMA_TCD define
Add comments in imxrt.h for clock gate requirements
Fix MTP count of bytes transferred (Kurt E)
Improve usbMIDI.send_now() on Teensy 3.x (Robert Jonkman)
Improve Stream comptibility with newer Arduino (Kurt E)
Audio add play queue setMaxBuffers() (Mark T)
Audio add play queue play() for raw data (Mark T)
Update FastLED to 3.4
FastLED fix OctoWS2811 driver on Teensy 4 (Shawn Silverman)
FastLED fix WS2812B timing on Teensy 4
OctoWS2811 add BasicTest_FastLED example
FreqCount fix for reading less slower than gate interval (mjs513)
FreqCount add missing end() function (mjs513)
LittleFS update internal littlefs to version 2.4.1 (mjs513)
Tlc5940 minor update for compiler flag setting (Adam Phelps)
OneWire minor updates for non-Teensy boards
USBHost_t36 fix HIDDumper example for Linux (Kurt E)
USBHost_t36 increase enum buffer for complex MIDI devices (Robert Jonkman)
Improve Teensy 4 Secure fusewrite and locksecuremode
Allow some old Teensy 4.x boards to run EHEX files
Add usage info with -h to teensy_post_compile and teensy_ports
Fix teensy_ports -L on Windows
Support for Arduino 1.8.18
SD faster detection of SDIO media change (KurtE)
SdFat fix SDIO on MicroMod (mjs513)
Fix pins 38 & 39 on MicroMod
LittleFS improve erase+write speed for NOR flash chips
LittleFS fix FRAM defines
LittleFS add Write_Speed_Test example
Fix PXP_PS_CTRL register defines
Fix USB receive packet loss with MTP on Teensy 4
Audio fixes for very small buffer size (Eric Fontaine)
FreqCount fix 1st reading on Teensy 4 (mjs513)
Teensy Loader verbose info clearer Standard vs Lockable
Drop Arduino 1.8.18
SdFat use same SDIO signal strength on all Teensy 4 (mjs513)
More MicroMod & Teensy 4 pin 38 & 39 fixes
Fix AudioPlayQueue internal stall (h4yn0nnym0u5e)
Add AudioControlCS42448 functions (modularev)
AudioInputAnalog compile on Teensy LC
Update FlexCAN_T4
Fix ILI9488_t3 examples (KurtE)
Update IRremote
LittleFS add LittleFS_SPI & LittleFS_QSPI wrappers (KurtE)
Fix LittleFS examples (mjs513)
Remove unneed LittleFS RAM cache flush (Defragster)
Fix OctoWS2811 VideoDisplay_Teensy4 extra cases (timethy96)
RA8875 examples fixed (KurtE)
RadioHead examples fixed (mjs513)
RadioHead fixes for Teensy 2
Snooze examples fixed (KurtE)
ST7789_t3 examples fixed (KurtE)
TeensyThreads updated
TFT_ILI9163C examples fixed
XPT2046_Touchscreen threshold adjusted (Andrew Kroll)
Fix SD example SdFat_Usage on Teensy 2.0
Fix SdFat example BackwardCompatibility on Teensy 2.0
SoftwareSerial add bool operator
Fix SD src-utility conflict when installed on top of 1.53 with Arduino 1.8.5-1.8.9
Audio fix compiler errors & warnings with Teensy LC
Audio Fix MidiSynthKeyboard example on Teensy 4
Audio async spdif example to compile on all boards
ILI9488_t3 fix compile errors in examples (KurtE)
ILI9488_t3 better document examples (mjs513)
LittleFS fix RAM Test_Integrity on Teensy 3.5 & 3.6 (Defragster)
LittleFS add Cypress and Fuji 2MBit FRAM support (KurtE)
MIDI fix DualMerger example
Fix Snooze hibernate/sd_datalogger example
SD & LittleFS listfiles PrintTime check valid month
Fix Print:rintf to call va_end (Shawn Silverman)
SD getModifyTime getCreateTime check 0 from SdFat (KurtE)
https://www.pjrc.com/teensy/td_download.html
Quick summary: 1.56 brings support for Arduino 1.8.19 and many fixes and improvements. Teensy 4.0, 4.1, MicroMod get a bootloader update which allows LittleFS_Program filesystem to persist across code uploads.
Changes since 1.56-beta6:
SD & LittleFS listfiles PrintTime check valid month
Fix Print:rintf to call va_end (Shawn Silverman)
SD getModifyTime getCreateTime check 0 from SdFat (KurtE)
Complete list of changes since 1.55:
Support for Arduino 1.8.19
Fix serial monitor stall on Windows
Fix upload failure to locked Teensy 4 if button pressed
FS.h support file create and modify time
SD support file create and modify time
SD automatically uses RTC
LittleFS support file create and modify time
LittleFS automatically uses RTC
Add makeTime, breakTime, DateTimeFields
Fix serial monitor regression with MTP on Linux
Fix digitalPinHasPWM for higher pin numbers on Teensy 4
MTP configure event endpoint on Teensy 4
Add FS format() and mediaPresent()
Add String compatibility to FS,SD,LittleFS,etc
Add LittleFS format() (mjs513)
Add SD format() and mediaPresent()
Update SdFat to version 2.1.0 and enable UTF8 filenames
Edit SdFat examples to compile on Teensy 3 & 4
Audio fix PT8211 when no audio data input (Frank B)
Audio i2s2 slave mode (alex6679)
Update FastCRC (Frank B)
USBHost_t36 HID support 1000 Hz update (Kurt E)
USBHost_t36 Keyboard forward API and example (Kurt E)
Reduce wasted memory during linking (Frank B)
Fix MTP detection on Linux
Fix serial monitor on Linux with MTP
Fix rare serial monitor stall on Windows
Fix rare Null Pointer Exception when closing serial monitor
Teensy Loader updates Teensy 4.0, 4.1, MicroMod to bootloader 1.07
Improve SD.mediaPresent()
Fix SD compile error on Teensy LC
Show helpful error if original SdFat used
Fix SdFat example compile errors, FsFile & SD_FAT_TYPE
Delete SdFat examples not needed for Teensy
Improve SdFat format speed with SHARED_SPI
Improve SdFat free cluster count speed with SHARED_SPI
Add SdFat restart(), to reinitialize hardware & card
SdFat FAT16/32 format use existing buffer (Kurt E)
SdFat support for GPT partitions (Kurt E)
SdFat fix use of USE_SIMPLE_LITTLE_ENDIAN
SdFat fix exfat corruption when using timestamps (Kurt E)
Wire use inline functions for AVR
Wire increase buffer size on Teensy 3 & 4
Wire fix ambiguous requestFrom with bool
FS use block write (Kurt E)
Fix IMXRT_DMA_TCD define
Add comments in imxrt.h for clock gate requirements
Fix MTP count of bytes transferred (Kurt E)
Improve usbMIDI.send_now() on Teensy 3.x (Robert Jonkman)
Improve Stream comptibility with newer Arduino (Kurt E)
Audio add play queue setMaxBuffers() (Mark T)
Audio add play queue play() for raw data (Mark T)
Update FastLED to 3.4
FastLED fix OctoWS2811 driver on Teensy 4 (Shawn Silverman)
FastLED fix WS2812B timing on Teensy 4
OctoWS2811 add BasicTest_FastLED example
FreqCount fix for reading less slower than gate interval (mjs513)
FreqCount add missing end() function (mjs513)
LittleFS update internal littlefs to version 2.4.1 (mjs513)
Tlc5940 minor update for compiler flag setting (Adam Phelps)
OneWire minor updates for non-Teensy boards
USBHost_t36 fix HIDDumper example for Linux (Kurt E)
USBHost_t36 increase enum buffer for complex MIDI devices (Robert Jonkman)
Improve Teensy 4 Secure fusewrite and locksecuremode
Allow some old Teensy 4.x boards to run EHEX files
Add usage info with -h to teensy_post_compile and teensy_ports
Fix teensy_ports -L on Windows
Support for Arduino 1.8.18
SD faster detection of SDIO media change (KurtE)
SdFat fix SDIO on MicroMod (mjs513)
Fix pins 38 & 39 on MicroMod
LittleFS improve erase+write speed for NOR flash chips
LittleFS fix FRAM defines
LittleFS add Write_Speed_Test example
Fix PXP_PS_CTRL register defines
Fix USB receive packet loss with MTP on Teensy 4
Audio fixes for very small buffer size (Eric Fontaine)
FreqCount fix 1st reading on Teensy 4 (mjs513)
Teensy Loader verbose info clearer Standard vs Lockable
Drop Arduino 1.8.18
SdFat use same SDIO signal strength on all Teensy 4 (mjs513)
More MicroMod & Teensy 4 pin 38 & 39 fixes
Fix AudioPlayQueue internal stall (h4yn0nnym0u5e)
Add AudioControlCS42448 functions (modularev)
AudioInputAnalog compile on Teensy LC
Update FlexCAN_T4
Fix ILI9488_t3 examples (KurtE)
Update IRremote
LittleFS add LittleFS_SPI & LittleFS_QSPI wrappers (KurtE)
Fix LittleFS examples (mjs513)
Remove unneed LittleFS RAM cache flush (Defragster)
Fix OctoWS2811 VideoDisplay_Teensy4 extra cases (timethy96)
RA8875 examples fixed (KurtE)
RadioHead examples fixed (mjs513)
RadioHead fixes for Teensy 2
Snooze examples fixed (KurtE)
ST7789_t3 examples fixed (KurtE)
TeensyThreads updated
TFT_ILI9163C examples fixed
XPT2046_Touchscreen threshold adjusted (Andrew Kroll)
Fix SD example SdFat_Usage on Teensy 2.0
Fix SdFat example BackwardCompatibility on Teensy 2.0
SoftwareSerial add bool operator
Fix SD src-utility conflict when installed on top of 1.53 with Arduino 1.8.5-1.8.9
Audio fix compiler errors & warnings with Teensy LC
Audio Fix MidiSynthKeyboard example on Teensy 4
Audio async spdif example to compile on all boards
ILI9488_t3 fix compile errors in examples (KurtE)
ILI9488_t3 better document examples (mjs513)
LittleFS fix RAM Test_Integrity on Teensy 3.5 & 3.6 (Defragster)
LittleFS add Cypress and Fuji 2MBit FRAM support (KurtE)
MIDI fix DualMerger example
Fix Snooze hibernate/sd_datalogger example
SD & LittleFS listfiles PrintTime check valid month
Fix Print:rintf to call va_end (Shawn Silverman)
SD getModifyTime getCreateTime check 0 from SdFat (KurtE)