diff --git a/requirements.txt b/requirements.txt
index 4f98342..7bb55eb 100755
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,5 @@
+python>=3.5.0
 bitstring>=3.1.5
 bitarray>=0.8.1
 Twisted>=16.3.0
-dmr_utils3>=0.1.19
\ No newline at end of file
+dmr_utils3>=0.1.19