1 files changed, 7 insertions, 0 deletions
diff --git a/docs/modules/account_validity_callbacks.md b/docs/modules/account_validity_callbacks.md
index 80684b7828..836bda70bf 100644
--- a/docs/modules/account_validity_callbacks.md
+++ b/docs/modules/account_validity_callbacks.md
@@ -22,6 +22,11 @@ If the module returns `True`, the current request will be denied with the error
 `ORG_MATRIX_EXPIRED_ACCOUNT` and the HTTP status code 403. Note that this doesn't
 invalidate the user's access token.
 
+If multiple modules implement this callback, they will be considered in order. If a
+callback returns `None`, Synapse falls through to the next one. The value of the first
+callback that does not return `None` will be used. If this happens, Synapse will not call
+any of the subsequent implementations of this callback.
+
 ### `on_user_registration`
 
 ```python
@@ -31,3 +36,5 @@ async def on_user_registration(user: str) -> None
 Called after successfully registering a user, in case the module needs to perform extra
 operations to keep track of them. (e.g. add them to a database table). The user is
 represented by their Matrix user ID.
+
+If multiple modules implement this callback, Synapse runs them all in order.