diff --git a/software/hwio-raspberry/requirements.txt b/software/hwio-raspberry/requirements.txt
index d587dca..c4cafe8 100644
--- a/software/hwio-raspberry/requirements.txt
+++ b/software/hwio-raspberry/requirements.txt
@@ -1,4 +1,4 @@
-pymodbus
+pymodbus==3.7.4
 smbus
 nmcli
 RPi.GPIO
diff --git a/software/hwio-virtual/requirements.txt b/software/hwio-virtual/requirements.txt
index ac7086b..16bc330 100644
--- a/software/hwio-virtual/requirements.txt
+++ b/software/hwio-virtual/requirements.txt
@@ -1,2 +1,2 @@
-pymodbus
+pymodbus==3.7.4
 nicegui
diff --git a/tests/requirements.txt b/tests/requirements.txt
index 2a921c5..1cdef6c 100644
--- a/tests/requirements.txt
+++ b/tests/requirements.txt
@@ -1,7 +1,7 @@
-pytest
-pytest-cov
-pytest-asyncio
-pymodbus
-asyncio
-asyncua
-requests
\ No newline at end of file
+pytest==8.3.4
+pytest-cov==6.0.0
+pytest-asyncio==0.25.0
+pymodbus==3.7.4
+asyncio==3.4.3
+asyncua==1.1.0
+requests==2.25.1
diff --git a/tests/test_modbus.py b/tests/test_modbus.py
index 4c519bc..fef027c 100644
--- a/tests/test_modbus.py
+++ b/tests/test_modbus.py
@@ -51,7 +51,7 @@ def test_read_holding_register(modbus_client):
     """
     # Address of the register (Modbus address is often 0-based)
     register_address = 1
-    result = modbus_client.read_holding_registers(register_address, 1)
+    result = modbus_client.read_holding_registers(register_address, count=1)
     
     # Check if we received a valid response
     assert result is not None, "No response from the Modbus server"
@@ -73,7 +73,7 @@ def test_write_single_register(modbus_client):
     assert not result.isError(), f"Modbus error: {result}"
 
     # Verify that the value was written correctly by reading it back
-    read_result = modbus_client.read_holding_registers(register_address, 1)
+    read_result = modbus_client.read_holding_registers(register_address, count=1)
     assert read_result.registers[0] == value_to_write, f"Expected {value_to_write}, got {read_result.registers[0]}"
 
 @pytest.mark.asyncio