1 files changed, 5 insertions, 0 deletions
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 8a2b73b75e..fca6151feb 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -106,6 +106,9 @@ CONDITIONAL_REQUIREMENTS = {
         "pysaml2>=4.5.0;python_version>='3.6'",
     ],
     "oidc": ["authlib>=0.14.0"],
+    # systemd-python is necessary for logging to the systemd journal via
+    # `systemd.journal.JournalHandler`, as is documented in
+    # `contrib/systemd/log_config.yaml`.
     "systemd": ["systemd-python>=231"],
     "url_preview": ["lxml>=3.5.0"],
     "sentry": ["sentry-sdk>=0.7.2"],
@@ -116,6 +119,8 @@ CONDITIONAL_REQUIREMENTS = {
     "redis": ["txredisapi>=1.4.7", "hiredis"],
 }
 
+CONDITIONAL_REQUIREMENTS["mypy"] = ["mypy==0.790", "mypy-zope==0.2.8"]
+
 ALL_OPTIONAL_REQUIREMENTS = set()  # type: Set[str]
 
 for name, optional_deps in CONDITIONAL_REQUIREMENTS.items():