diff --git a/.github/workflows/cygwin_build.yml b/.github/workflows/cygwin_build.yml
index 4157e219af2d6..d3c33e1de11a3 100644
--- a/.github/workflows/cygwin_build.yml
+++ b/.github/workflows/cygwin_build.yml
@@ -55,7 +55,7 @@ jobs:
         shell: C:\cygwin\bin\bash.exe -eo pipefail '{0}'
         run: >-
           ln -sf /usr/bin/python3.7 /usr/bin/python && ln -sf /usr/bin/pip3.7 /usr/bin/pip &&
-          python -m pip install --progress-bar off empy pexpect &&
+          python -m pip install --progress-bar off empy==3.3.4 pexpect &&
           python -m pip install --progress-bar off dronecan --upgrade &&
           cp /usr/bin/ccache /usr/local/bin/ &&
           cd /usr/local/bin && ln -s ccache /usr/local/bin/gcc &&
diff --git a/.github/workflows/esp32_build.yml b/.github/workflows/esp32_build.yml
index f24d8190d5608..fbceeb8f16306 100644
--- a/.github/workflows/esp32_build.yml
+++ b/.github/workflows/esp32_build.yml
@@ -62,7 +62,7 @@ jobs:
           ./install.sh
           source ./export.sh
           cd ../..
-          python -m pip install --progress-bar off future lxml pymavlink MAVProxy pexpect flake8 geocoder empy dronecan
+          python -m pip install --progress-bar off future lxml pymavlink MAVProxy pexpect flake8 geocoder empy==3.3.4 dronecan
           which cmake
           ./waf configure --board ${{matrix.config}}
           ./waf plane
diff --git a/Tools/AP_Periph/wscript b/Tools/AP_Periph/wscript
index d6a733b5ffafd..a684bd683719a 100644
--- a/Tools/AP_Periph/wscript
+++ b/Tools/AP_Periph/wscript
@@ -7,7 +7,7 @@ import sys
 try:
     import em
 except ImportError:
-    print("you need to install empy with 'python -m pip install empy'")
+    print("you need to install empy with 'python -m pip install empy==3.3.4'")
     sys.exit(1)
 
 try:
diff --git a/Tools/ardupilotwaf/chibios.py b/Tools/ardupilotwaf/chibios.py
index 46d2bb2ca0033..6da05e0b8429b 100644
--- a/Tools/ardupilotwaf/chibios.py
+++ b/Tools/ardupilotwaf/chibios.py
@@ -112,7 +112,7 @@ def get_full_wsl2_error_msg(self, error_msg):
         and make sure to add it to your path during the installation. Once installed, run this
         command in Powershell or Command Prompt to install some packages:
         
-        pip.exe install empy pyserial
+        pip.exe install empy==3.3.4 pyserial
         ****************************************
         ****************************************
         """ % error_msg)
diff --git a/Tools/environment_install/install-prereqs-arch.sh b/Tools/environment_install/install-prereqs-arch.sh
index 2681c38d9f32c..b5437f5c1630d 100755
--- a/Tools/environment_install/install-prereqs-arch.sh
+++ b/Tools/environment_install/install-prereqs-arch.sh
@@ -26,7 +26,7 @@ BASE_PKGS="base-devel ccache git gsfonts tk wget gcc"
 SITL_PKGS="python-pip python-setuptools python-wheel python-wxpython opencv python-numpy python-scipy"
 PX4_PKGS="lib32-glibc zip zlib ncurses"
 
-PYTHON_PKGS="future lxml pymavlink MAVProxy pexpect argparse matplotlib pyparsing geocoder pyserial empy dronecan"
+PYTHON_PKGS="future lxml pymavlink MAVProxy pexpect argparse matplotlib pyparsing geocoder pyserial empy==3.3.4 dronecan"
 
 # GNU Tools for ARM Embedded Processors
 # (see https://launchpad.net/gcc-arm-embedded/)
diff --git a/Tools/environment_install/install-prereqs-mac.sh b/Tools/environment_install/install-prereqs-mac.sh
index 906ad0022a0bd..91ed9cf602b59 100755
--- a/Tools/environment_install/install-prereqs-mac.sh
+++ b/Tools/environment_install/install-prereqs-mac.sh
@@ -159,7 +159,7 @@ if [[ $DO_AP_STM_ENV -eq 1 ]]; then
     install_arm_none_eabi_toolchain
 fi
 
-PYTHON_PKGS="future lxml pymavlink MAVProxy pexpect geocoder flake8 empy dronecan"
+PYTHON_PKGS="future lxml pymavlink MAVProxy pexpect geocoder flake8 empy==3.3.4 dronecan"
 # add some Python packages required for commonly-used MAVProxy modules and hex file generation:
 if [[ $SKIP_AP_EXT_ENV -ne 1 ]]; then
     PYTHON_PKGS="$PYTHON_PKGS intelhex gnureadline"
diff --git a/Tools/environment_install/install-prereqs-ubuntu.sh b/Tools/environment_install/install-prereqs-ubuntu.sh
index 3f2a54458a7bd..7d34dd1be38f7 100755
--- a/Tools/environment_install/install-prereqs-ubuntu.sh
+++ b/Tools/environment_install/install-prereqs-ubuntu.sh
@@ -144,9 +144,9 @@ fi
 BASE_PKGS="build-essential ccache g++ gawk git make wget"
 if [ ${RELEASE_CODENAME} == 'bionic' ]; then
     # use fixed version for package that drop python2 support
-    PYTHON_PKGS="future lxml pymavlink MAVProxy pexpect flake8==3.7.9 requests==2.27.1 monotonic==1.6 geocoder empy configparser==4.0.2 click==7.1.2 decorator==4.4.2 dronecan"
+    PYTHON_PKGS="future lxml pymavlink MAVProxy pexpect flake8==3.7.9 requests==2.27.1 monotonic==1.6 geocoder empy==3.3.4 configparser==4.0.2 click==7.1.2 decorator==4.4.2 dronecan"
 else
-    PYTHON_PKGS="future lxml pymavlink MAVProxy pexpect flake8 geocoder empy dronecan"
+    PYTHON_PKGS="future lxml pymavlink MAVProxy pexpect flake8 geocoder empy==3.3.4 dronecan"
 fi
 
 # add some Python packages required for commonly-used MAVProxy modules and hex file generation:
diff --git a/Tools/environment_install/install-prereqs-windows-andAPMSource.ps1 b/Tools/environment_install/install-prereqs-windows-andAPMSource.ps1
index e1bf9465c4f07..2076ce1f588d6 100644
--- a/Tools/environment_install/install-prereqs-windows-andAPMSource.ps1
+++ b/Tools/environment_install/install-prereqs-windows-andAPMSource.ps1
@@ -19,7 +19,7 @@ Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -
 Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'ln -sf /usr/bin/pip3.7 /usr/bin/pip'"
 
 Write-Output "Downloading extra Python packages (5/8)"
-Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'pip install empy pyserial pymavlink intelhex dronecan pexpect'"
+Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'pip install empy==3.3.4 pyserial pymavlink intelhex dronecan pexpect'"
 
 Write-Output "Downloading APM source (6/8)"
 Copy-Item "APM_install.sh" -Destination "C:\cygwin64\home"
diff --git a/Tools/environment_install/install-prereqs-windows.ps1 b/Tools/environment_install/install-prereqs-windows.ps1
index 5529c9f0c11dc..15bac628949e8 100644
--- a/Tools/environment_install/install-prereqs-windows.ps1
+++ b/Tools/environment_install/install-prereqs-windows.ps1
@@ -19,7 +19,7 @@ Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -
 Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'ln -sf /usr/bin/pip3.7 /usr/bin/pip'"
 
 Write-Output "Downloading extra Python packages (5/7)"
-Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'pip install empy pyserial pymavlink intelhex dronecan pexpect'"
+Start-Process -wait -FilePath "C:\cygwin64\bin\bash" -ArgumentList "--login -i -c 'pip install empy==3.3.4 pyserial pymavlink intelhex dronecan pexpect'"
 
 Write-Output "Installing ARM GCC Compiler 10-2020-Q4-Major (6/7)"
 & $PSScriptRoot\gcc-arm-none-eabi-10-2020-q4-major-win32.exe /S /P /R
diff --git a/Tools/scripts/configure-ci.sh b/Tools/scripts/configure-ci.sh
index e7a4c6a60dd80..a547b729fce17 100755
--- a/Tools/scripts/configure-ci.sh
+++ b/Tools/scripts/configure-ci.sh
@@ -101,5 +101,4 @@ python -m pip install --progress-bar off --user -U argparse pyserial pexpect fut
 python -m pip install --progress-bar off --user -U intelhex
 python -m pip install --progress-bar off --user -U numpy
 python -m pip install --progress-bar off --user -U edn_format
-python -m pip install --progress-bar off --user -U empy
-
+python -m pip install --progress-bar off --user -U empy==3.3.4