1 files changed, 3 insertions, 1 deletions
diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml
index edfde05a23..493ea9ee9e 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -763,7 +763,9 @@ uploads_path: "DATADIR/uploads"
 # This means that, if a validity period is set, and Synapse is restarted (it will
 # then derive an expiration date from the current validity period), and some time
 # after that the validity period changes and Synapse is restarted, the users'
-# expiration dates won't be updated unless their account is manually renewed.
+# expiration dates won't be updated unless their account is manually renewed. This
+# date will be randomly selected within a range [now + period - d ; now + period],
+# where d is equal to 10% of the validity period.
 #
 #account_validity:
 #  enabled: True