diff --git a/README.md b/README.md
index 7fd42df..1294162 100644
--- a/README.md
+++ b/README.md
@@ -28,9 +28,11 @@ We will retrieve these informations:
 
 1.2 Install requirements :
 
+- You need python >= 3.6
+
 - On debian based distribution you can install some requirement from repos: 
  
- ```sudo apt-get install python3-typing-extensions python3-pandas python3-plotly python3-paho-mqtt  python3-six python3-dateutil python3-brotli  libblas-dev  liblapack-dev gfortran python3-pycryptodome python3-numpy libatlas3-base```
+ ```sudo apt-get install python3-typing-extensions python3-pandas python3-plotly python3-paho-mqtt  python3-six python3-dateutil python3-brotli  libblas-dev  liblapack-dev gfortran python3-pycryptodome python3-numpy libatlas3-base python3-cryptography```
     
 - For everyone :
       ```pip3 install -r requirements.txt```
diff --git a/app_decoder.py b/app_decoder.py
index 960d245..53d3bbc 100755
--- a/app_decoder.py
+++ b/app_decoder.py
@@ -72,7 +72,7 @@ def save_key_to_pem(pfx_data, pfx_password):
 current_dir = os.getcwd()
 script_dir = dir_path = os.path.dirname(os.path.realpath(__file__))
 if sys.version_info < (3, 6):
-    raise RuntimeError("This application requres Python 3.6+")
+    raise RuntimeError("This application requires Python 3.6+")
 
 if not argv[1].endswith(".apk"):
     print("No apk given")
diff --git a/requirements.txt b/requirements.txt
index ddc8c37..dc113c9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@ paho-mqtt>=1.5.0
 dash>=1.18.0
 dash_daq
 plotly>=4
-cryptography>=3.0
+cryptography>=2.6
 Werkzeug>=1.0.0
 pandas
 oauth2_client