diff --git a/boards/teensy40.json b/boards/teensy40.json
new file mode 100644
index 0000000..05da1ee
--- /dev/null
+++ b/boards/teensy40.json
@@ -0,0 +1,31 @@
+{
+  "build": {
+    "core": "teensy4",
+    "cpu": "cortex-m7",
+    "extra_flags": "-D__IMXRT1062__ -DTEENSY40",
+    "f_cpu": "600000000",
+    "ldscript": "imxrt1062.ld",
+    "mcu": "imxrt1062"
+  },
+  "connectivity": [
+    "can"
+  ],
+  "debug": {
+    "jlink_device": "MIMXRT1062xxxxA"
+  },
+  "frameworks": [
+    "arduino"
+  ],
+  "name": "Teensy 4.0",
+  "upload": {
+    "maximum_ram_size": 1048576,
+    "maximum_size": 2031616,
+    "protocol": "teensy-gui",
+    "protocols": [
+      "teensy-gui",
+      "jlink"
+    ]
+  },
+  "url": "https://www.pjrc.com/store/teensy40.html",
+  "vendor": "Teensy"
+}
diff --git a/builder/frameworks/arduino.py b/builder/frameworks/arduino.py
index 44fe6fd..b2acf1a 100644
--- a/builder/frameworks/arduino.py
+++ b/builder/frameworks/arduino.py
@@ -33,6 +33,8 @@
 
 FRAMEWORK_DIR = platform.get_package_dir("framework-arduinoteensy")
 FRAMEWORK_VERSION = platform.get_package_version("framework-arduinoteensy")
+BUILD_CORE = env.BoardConfig().get("build.core")
+
 assert isdir(FRAMEWORK_DIR)
 
 BUILTIN_USB_FLAGS = (
@@ -61,6 +63,11 @@
 if not set(env.get("CPPDEFINES", [])) & set(BUILTIN_USB_FLAGS):
     env.Append(CPPDEFINES=["USB_SERIAL"])
 
+env.Replace(
+    SIZEPROGREGEXP=r"^(?:\.text|\.text\.progmem|\.text\.itcm|\.data)\s+([0-9]+).*",
+    SIZEDATAREGEXP=r"^(?:\.usbdescriptortable|\.dmabuffers|\.usbbuffers|\.data|\.bss|\.bss\.dma|\.noinit|\.text\.itcm)\s+([0-9]+).*"
+)
+
 env.Append(
     CPPDEFINES=[
         ("ARDUINO", 10805),
@@ -68,7 +75,7 @@
     ],
 
     CPPPATH=[
-        join(FRAMEWORK_DIR, "cores", env.BoardConfig().get("build.core"))
+        join(FRAMEWORK_DIR, "cores", BUILD_CORE)
     ],
 
     LIBSOURCE_DIRS=[
@@ -76,7 +83,7 @@
     ]
 )
 
-if "BOARD" in env and env.BoardConfig().get("build.core") == "teensy":
+if "BOARD" in env and BUILD_CORE == "teensy":
     env.Append(
         ASFLAGS=["-x", "assembler-with-cpp"],
 
@@ -91,7 +98,8 @@
         CXXFLAGS=[
             "-fno-exceptions",
             "-felide-constructors",
-            "-std=gnu++11"
+            "-std=gnu++11",
+            "-fpermissive"
         ],
 
         CPPDEFINES=[
@@ -107,7 +115,7 @@
 
         LIBS=["m"]
     )
-elif "BOARD" in env and env.BoardConfig().get("build.core") == "teensy3":
+elif "BOARD" in env and BUILD_CORE in ("teensy3", "teensy4"):
     env.Replace(
         AR="arm-none-eabi-gcc-ar",
         RANLIB="$AR"
@@ -131,7 +139,8 @@
             "-felide-constructors",
             "-fno-rtti",
             "-std=gnu++14",
-            "-Wno-error=narrowing"
+            "-Wno-error=narrowing",
+            "-fpermissive"
         ],
 
         CPPDEFINES=[
@@ -152,16 +161,20 @@
         LIBS=["m", "stdc++"]
     )
 
-    if env.BoardConfig().id_ in ("teensy35", "teensy36"):
+    if env.BoardConfig().id_ in ("teensy35", "teensy36", "teensy40"):
+        fpv_version = "4-sp"
+        if env.BoardConfig().id_ == "teensy40":
+            fpv_version = "5"
+
         env.Append(
             CCFLAGS=[
                 "-mfloat-abi=hard",
-                "-mfpu=fpv4-sp-d16"
+                "-mfpu=fpv%s-d16" % fpv_version
             ],
 
             LINKFLAGS=[
                 "-mfloat-abi=hard",
-                "-mfpu=fpv4-sp-d16"
+                "-mfpu=fpv%s-d16" % fpv_version
             ]
         )
 
@@ -254,13 +267,15 @@
         math_lib = math_lib % "M4lf"
     elif board in ("teensy30", "teensy31"):
         math_lib = math_lib % "M4l"
+    elif board == "teensy40":
+        math_lib = math_lib % "M7lfsp"
     else:
         math_lib = math_lib % "M0l"
 
     env.Prepend(LIBS=[math_lib])
 
 # Teensy 2.x Core
-if env.BoardConfig().get("build.core") == "teensy":
+if BUILD_CORE == "teensy":
     env.Append(CPPPATH=[join(FRAMEWORK_DIR, "cores")])
 
     # search relative includes in teensy directories
@@ -281,7 +296,7 @@
         with open(file_path, "w", encoding="latin-1") as fp:
             fp.write(content)
 else:
-    env.Prepend(LIBPATH=[join(FRAMEWORK_DIR, "cores", "teensy3")])
+    env.Prepend(LIBPATH=[join(FRAMEWORK_DIR, "cores", BUILD_CORE)])
 
 #
 # Target: Build Core Library
@@ -303,7 +318,7 @@
 
 libs.append(env.BuildLibrary(
     join("$BUILD_DIR", "FrameworkArduino"),
-    join(FRAMEWORK_DIR, "cores", env.BoardConfig().get("build.core"))
+    join(FRAMEWORK_DIR, "cores", BUILD_CORE)
 ))
 
 env.Prepend(LIBS=libs)
diff --git a/builder/main.py b/builder/main.py
index 1b5a026..e328f52 100644
--- a/builder/main.py
+++ b/builder/main.py
@@ -88,7 +88,7 @@
     if not env.get("PIOFRAMEWORK"):
         env.SConscript("frameworks/_bare_avr.py")
 
-elif "BOARD" in env and board_config.get("build.core") == "teensy3":
+elif "BOARD" in env and board_config.get("build.core") in ("teensy3", "teensy4"):
     env.Replace(
         AR="arm-none-eabi-ar",
         AS="arm-none-eabi-as",
@@ -138,6 +138,7 @@
 
 target_elf = None
 if "nobuild" in COMMAND_LINE_TARGETS:
+    target_elf = join("$BUILD_DIR", "${PROGNAME}.elf")
     target_firm = join("$BUILD_DIR", "${PROGNAME}.hex")
 else:
     target_elf = env.BuildProgram()
diff --git a/examples/arduino-blink/platformio.ini b/examples/arduino-blink/platformio.ini
index 252b3bc..8e1f8db 100644
--- a/examples/arduino-blink/platformio.ini
+++ b/examples/arduino-blink/platformio.ini
@@ -41,3 +41,8 @@ board = teensy35
 platform = teensy
 framework = arduino
 board = teensy36
+
+[env:teensy40]
+platform = teensy
+framework = arduino
+board = teensy40 
diff --git a/examples/arduino-internal-libs/platformio.ini b/examples/arduino-internal-libs/platformio.ini
index de4ce55..13e5a6c 100644
--- a/examples/arduino-internal-libs/platformio.ini
+++ b/examples/arduino-internal-libs/platformio.ini
@@ -41,3 +41,8 @@ board = teensy35
 platform = teensy
 framework = arduino
 board = teensy36
+
+[env:teensy40]
+platform = teensy
+framework = arduino
+board = teensy40
diff --git a/platform.json b/platform.json
index 2211c26..1bf00de 100644
--- a/platform.json
+++ b/platform.json
@@ -12,7 +12,7 @@
     "type": "git",
     "url": "https://github.com/platformio/platform-teensy.git"
   },
-  "version": "4.3.0",
+  "version": "4.4.0",
   "packageRepositories": [
     "https://dl.bintray.com/platformio/dl-packages/manifest.json",
     "http://dl.platformio.org/packages/manifest.json"
@@ -41,12 +41,12 @@
     "framework-arduinoteensy": {
       "type": "framework",
       "optional": true,
-      "version": "~1.145.0"
+      "version": "~1.147.0"
     },
     "framework-mbed": {
       "type": "framework",
       "optional": true,
-      "version": "~5.51203.190509"
+      "version": "~5.51203.0"
     },
     "tool-teensy": {
       "type": "uploader",