diff --git a/README.md b/README.md
index 9895054..df8a3f6 100644
--- a/README.md
+++ b/README.md
@@ -277,6 +277,18 @@ end: '{{ now() }}'
 
 You can automatically track new versions of this component and update it by [HACS][hacs].
 
+## Troubleshooting
+
+To enable debug logs use this configuration:
+```yaml
+# Example configuration.yaml entry
+logger:
+  default: error
+  logs:
+    custom_components.average: debug
+```
+... then restart HA.
+
 ## Contributions are welcome!
 
 This is an active open-source project. We are always open to people who want to
diff --git a/custom_components/average/sensor.py b/custom_components/average/sensor.py
index 186f01e..74d54c8 100644
--- a/custom_components/average/sensor.py
+++ b/custom_components/average/sensor.py
@@ -302,7 +302,8 @@ def _update_period(self):  # pylint: disable=r0912
             except (TemplateError, TypeError) as ex:
                 self.handle_template_exception(ex, "start")
                 return
-            start = dt_util.parse_datetime(start_rendered)
+            if isinstance(start_rendered, str):
+                start = dt_util.parse_datetime(start_rendered)
             if start is None:
                 try:
                     start = dt_util.as_local(
@@ -322,7 +323,8 @@ def _update_period(self):  # pylint: disable=r0912
             except (TemplateError, TypeError) as ex:
                 self.handle_template_exception(ex, "end")
                 return
-            end = dt_util.parse_datetime(end_rendered)
+            if isinstance(end_rendered, str):
+                end = dt_util.parse_datetime(end_rendered)
             if end is None:
                 try:
                     end = dt_util.as_local(
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 1c61057..a2dc454 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -2,7 +2,7 @@
 black==20.8b1
 flake8~=3.8
 mypy==0.790
-packaging~=20.7
+packaging~=20.8
 pre-commit~=2.9
 PyGithub==1.54
 pylint~=2.6
diff --git a/requirements.txt b/requirements.txt
index da2f084..7ed1447 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,2 @@
 voluptuous~=0.12
-homeassistant~=0.118
+homeassistant~=2021.1