diff --git a/README.md b/README.md
index a8a6dc9..2d68eaf 100644
--- a/README.md
+++ b/README.md
@@ -22,8 +22,8 @@ pip --version
 Then install with one of the following options:
 
 ```shell
-sudo python3 -m pip install --upgrade git+https://codeberg.org/privacy1st/execNotify
-sudo python3 -m pip install --upgrade .
+sudo python3 -m pip install --upgrade --force-reinstall git+https://codeberg.org/privacy1st/execNotify
+sudo python3 -m pip install --upgrade --force-reinstall .
 sudo python3 -m pip install --upgrade --index-url https://test.pypi.org/simple/ --no-deps de.p1st.exec-notify
 ```
 
diff --git a/setup.cfg b/setup.cfg
index ec56bbe..7bf6d63 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -3,7 +3,7 @@
 
 [metadata]
 name = de.p1st.exec_notify
-version = 0.1.8
+version = 0.1.9
 author = Daniel Langbein
 author_email = daniel@systemli.org
 description = mail notification if command fails
@@ -24,9 +24,7 @@ classifiers =
 package_dir =
     = src
 packages = find:
-; capture_output was added in 3.7
-; - https://docs.python.org/3/library/subprocess.html#subprocess.run
-python_requires = >=3.7
+python_requires = >=3.6
 
 [options.packages.find]
 where = src
diff --git a/setup.py b/setup.py
new file mode 100644
index 0000000..0abbd0a
--- /dev/null
+++ b/setup.py
@@ -0,0 +1,4 @@
+# This file is required for `pip install` on Ubuntu 18.04.
+# It loads `setup.cfg`.
+from setuptools import setup
+setup()
diff --git a/src/de/p1st/exec_notify/lib/exec.py b/src/de/p1st/exec_notify/lib/exec.py
index ad3bf23..87b903d 100644
--- a/src/de/p1st/exec_notify/lib/exec.py
+++ b/src/de/p1st/exec_notify/lib/exec.py
@@ -1,3 +1,4 @@
+import sys
 from typing import List
 from sys import stdin
 import subprocess
@@ -12,6 +13,19 @@ def execute(command: List[str]):
     :return: (exit_code, stdout, stderr)
     """
 
+    if sys.version_info.major == 3 and sys.version_info.minor < 7:
+        # capture_output was added in 3.7
+        # - https://docs.python.org/3/library/subprocess.html#subprocess.run
+
+        completed: subprocess.CompletedProcess = subprocess.run(
+            command,
+            stdin=stdin,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+            check=False,
+        )
+        return completed.returncode, str(completed.stdout), str(completed.stderr)
+
     completed: subprocess.CompletedProcess = subprocess.run(
         command,
         stdin=stdin,