1 files changed, 14 insertions, 0 deletions
diff --git a/docs/usage/configuration/config_documentation.md b/docs/usage/configuration/config_documentation.md
index 2228c18a6c..e688bc5cd8 100644
--- a/docs/usage/configuration/config_documentation.md
+++ b/docs/usage/configuration/config_documentation.md
@@ -2887,6 +2887,20 @@ Example configuration:
inhibit_user_in_use_error: true
```
---
+### `allow_underscore_prefixed_registration`
+
+Whether users are allowed to register with a underscore-prefixed localpart.
+By default, AppServices use prefixes like `_example` to namespace their
+associated ghost users. If turned on, this may result in clashes or confusion.
+Useful when provisioning users from an external identity provider.
+
+Defaults to false.
+
+Example configuration:
+```yaml
+allow_underscore_prefixed_registration: false
+```
+---
## User session management
---
### `session_lifetime`
|
