diff --git a/software/planktoscope-backend/README.md b/software/planktoscope-backend/README.md
index 43051de..7c45dfb 100644
--- a/software/planktoscope-backend/README.md
+++ b/software/planktoscope-backend/README.md
@@ -1,3 +1,7 @@
+<!--
+SPDX-License-Identifier: GPL-3.0-or-later
+-->
+
 # planktoscope-backend
 
 [![PyPI - Version](https://img.shields.io/pypi/v/planktoscope-backend.svg)](https://pypi.org/project/planktoscope-backend)
diff --git a/software/planktoscope-backend/src/planktoscope_backend/__about__.py b/software/planktoscope-backend/src/planktoscope_backend/__about__.py
index a56b2c4..56c781b 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/__about__.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/__about__.py
@@ -1,4 +1,7 @@
-# SPDX-FileCopyrightText: 2022-present Sebastian Wendel <s.wendel@sourceindex.de>
-#
-# SPDX-License-Identifier: MIT
-__version__ = '0.0.1'
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+# coding: utf-8
+# file generated by setuptools_scm
+# don't change, don't track in version control
+__version__ = version = '0.1.dev654+g9630e46.d19800101'
+__version_tuple__ = version_tuple = (0, 1, 'dev654', 'g9630e46.d19800101')
diff --git a/software/planktoscope-backend/src/planktoscope_backend/__init__.py b/software/planktoscope-backend/src/planktoscope_backend/__init__.py
index 2858071..1c36b0c 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/__init__.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/__init__.py
@@ -1,3 +1,4 @@
 # SPDX-FileCopyrightText: 2022-present Sebastian Wendel <s.wendel@sourceindex.de>
 #
+# SPDX-License-Identifier: GPL-3.0-or-later
 # SPDX-License-Identifier: MIT
diff --git a/software/planktoscope-backend/src/planktoscope_backend/_version.py b/software/planktoscope-backend/src/planktoscope_backend/_version.py
index 226bda1..a3ff69c 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/_version.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/_version.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # coding: utf-8
 # file generated by setuptools_scm
 # don't change, don't track in version control
diff --git a/software/planktoscope-backend/src/planktoscope_backend/display.py b/software/planktoscope-backend/src/planktoscope_backend/display.py
index e2c833b..491bdce 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/display.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/display.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # Logger library compatible with multiprocessing
 from loguru import logger
 
diff --git a/software/planktoscope-backend/src/planktoscope_backend/imager/__init__.py b/software/planktoscope-backend/src/planktoscope_backend/imager/__init__.py
index c37a034..5e700a6 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/imager/__init__.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/imager/__init__.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 ################################################################################
 # Practical Libraries
 ################################################################################
diff --git a/software/planktoscope-backend/src/planktoscope_backend/imager/raspimjpeg.py b/software/planktoscope-backend/src/planktoscope_backend/imager/raspimjpeg.py
index 5acbf4f..c529b4a 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/imager/raspimjpeg.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/imager/raspimjpeg.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 ################################################################################
 # Practical Libraries
 ################################################################################
diff --git a/software/planktoscope-backend/src/planktoscope_backend/imager/state_machine.py b/software/planktoscope-backend/src/planktoscope_backend/imager/state_machine.py
index 483208e..b3a6490 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/imager/state_machine.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/imager/state_machine.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # Logger library compatible with multiprocessing
 from loguru import logger
 
diff --git a/software/planktoscope-backend/src/planktoscope_backend/imager/streamer.py b/software/planktoscope-backend/src/planktoscope_backend/imager/streamer.py
index 01f1cea..6cf2dea 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/imager/streamer.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/imager/streamer.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 from loguru import logger
 
 import time
diff --git a/software/planktoscope-backend/src/planktoscope_backend/integrity.py b/software/planktoscope-backend/src/planktoscope_backend/integrity.py
index c2200af..903a304 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/integrity.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/integrity.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # This module calculates the checksum of created files and add them to and file called integrity.check
 # The file is composed as follows:
 # First, a header that starts by like so:
diff --git a/software/planktoscope-backend/src/planktoscope_backend/light.py b/software/planktoscope-backend/src/planktoscope_backend/light.py
index 5975e53..9a4d471 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/light.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/light.py
@@ -1,4 +1,7 @@
 #!/usr/bin/env python
+
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # Turn on using this command line :
 # python3.7 path/to/file/light.py on
 
diff --git a/software/planktoscope-backend/src/planktoscope_backend/main.py b/software/planktoscope-backend/src/planktoscope_backend/main.py
index 11231d3..6b6d516 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/main.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/main.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # Logger library compatible with multiprocessing
 from loguru import logger
 import sys
diff --git a/software/planktoscope-backend/src/planktoscope_backend/module.py b/software/planktoscope-backend/src/planktoscope_backend/module.py
index 8cf3bbf..7440e4b 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/module.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/module.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 ################################################################################
 # Practical Libraries
 ################################################################################
diff --git a/software/planktoscope-backend/src/planktoscope_backend/mqtt.py b/software/planktoscope-backend/src/planktoscope_backend/mqtt.py
index baaad2c..a2eeef8 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/mqtt.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/mqtt.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # Library for exchaning messages with Node-RED
 # We are using MQTT V3.1.1
 # The documentation for Paho can be found here:
diff --git a/software/planktoscope-backend/src/planktoscope_backend/segmenter/__init__.py b/software/planktoscope-backend/src/planktoscope_backend/segmenter/__init__.py
index b3662d8..856da71 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/segmenter/__init__.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/segmenter/__init__.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 ################################################################################
 # Practical Libraries
 ################################################################################
diff --git a/software/planktoscope-backend/src/planktoscope_backend/segmenter/ecotaxa.py b/software/planktoscope-backend/src/planktoscope_backend/segmenter/ecotaxa.py
index a87a616..1f52d52 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/segmenter/ecotaxa.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/segmenter/ecotaxa.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # Logger library compatible with multiprocessing
 from loguru import logger
 
diff --git a/software/planktoscope-backend/src/planktoscope_backend/segmenter/encoder.py b/software/planktoscope-backend/src/planktoscope_backend/segmenter/encoder.py
index 6eabaa4..597a0bc 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/segmenter/encoder.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/segmenter/encoder.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 import json
 import numpy as np
 
diff --git a/software/planktoscope-backend/src/planktoscope_backend/segmenter/operations.py b/software/planktoscope-backend/src/planktoscope_backend/segmenter/operations.py
index f9c09f9..290e16e 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/segmenter/operations.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/segmenter/operations.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # Logger library compatible with multiprocessing
 from loguru import logger
 
diff --git a/software/planktoscope-backend/src/planktoscope_backend/segmenter/streamer.py b/software/planktoscope-backend/src/planktoscope_backend/segmenter/streamer.py
index d7d592f..9409459 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/segmenter/streamer.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/segmenter/streamer.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 from loguru import logger
 
 import time
diff --git a/software/planktoscope-backend/src/planktoscope_backend/stepper.py b/software/planktoscope-backend/src/planktoscope_backend/stepper.py
index f4815fb..e191cc6 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/stepper.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/stepper.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # Libraries to control the steppers for focusing and pumping
 import adafruit_motor.stepper
 import adafruit_motorkit
@@ -23,6 +25,7 @@ class StepperWaveshare:
         self.step_pin = step_pin
         self.enable_pin = enable_pin
 
+        # TODO: refactor to use libgpiod
         RPi.GPIO.setmode(RPi.GPIO.BCM)
         RPi.GPIO.setwarnings(False)
         RPi.GPIO.setup(
diff --git a/software/planktoscope-backend/src/planktoscope_backend/uuidName.py b/software/planktoscope-backend/src/planktoscope_backend/uuidName.py
index 5f38eb4..cb5e3d3 100644
--- a/software/planktoscope-backend/src/planktoscope_backend/uuidName.py
+++ b/software/planktoscope-backend/src/planktoscope_backend/uuidName.py
@@ -1,3 +1,5 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
 # Very inspired by https://github.com/bgawalt/uuidBabyName
 import re, uuid, random, os
 
diff --git a/software/planktoscope-backend/tests/__init__.py b/software/planktoscope-backend/tests/__init__.py
index 2858071..1c36b0c 100644
--- a/software/planktoscope-backend/tests/__init__.py
+++ b/software/planktoscope-backend/tests/__init__.py
@@ -1,3 +1,4 @@
 # SPDX-FileCopyrightText: 2022-present Sebastian Wendel <s.wendel@sourceindex.de>
 #
+# SPDX-License-Identifier: GPL-3.0-or-later
 # SPDX-License-Identifier: MIT