diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml
index 8ff53d5cb4..13c0ddc7c5 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -753,20 +753,15 @@ 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.
-#
-# If set, the ``startup_job_max_delta`` optional setting will make the startup job
-# described above set a random expiration date between t + period  and
-# t + period + startup_job_max_delta, t being the date and time at which the job
-# sets the expiration date for a given user. This is useful for server admins that
-# want to avoid Synapse sending a lot of renewal emails at once.
+# expiration dates won't be updated unless their account is manually renewed. This
+# date will be randomly selected within a range [now + period ; now + period + d],
+# where d is equal to 10% of the validity period.
 #
 #account_validity:
 #  enabled: True
 #  period: 6w
 #  renew_at: 1w
 #  renew_email_subject: "Renew your %(app)s account"
-#  startup_job_max_delta: 2d
 
 # The user must provide all of the below types of 3PID when registering.
 #