diff --git a/setup.py b/setup.py
index 2353f1e..457d6e7 100644
--- a/setup.py
+++ b/setup.py
@@ -25,7 +25,7 @@ def read(*parts):
 setup(
     name="lttbc",
     author="European XFEL GmbH",
-    version="0.1.7",
+    version="0.1.9",
     include_dirs=[numpy.get_include(), get_script_path()],
     ext_modules=[lttbc_py],
     author_email="dennis.goeries@xfel.eu",
@@ -35,4 +35,5 @@ def read(*parts):
     license="MIT",
     install_requires=[
         'numpy'],
+    python_requires=">=3.5"
 )