diff --git a/config/upgrade.go b/config/upgrade.go
index 362c5ee..d3042c7 100644
--- a/config/upgrade.go
+++ b/config/upgrade.go
@@ -101,6 +101,7 @@ func DoUpgrade(helper *up.Helper) {
 	helper.Copy(up.Bool, "bridge", "encryption", "allow")
 	helper.Copy(up.Bool, "bridge", "encryption", "default")
 	helper.Copy(up.Bool, "bridge", "encryption", "require")
+	helper.Copy(up.Bool, "bridge", "encryption", "appservice")
 	helper.Copy(up.Str, "bridge", "encryption", "verification_levels", "receive")
 	helper.Copy(up.Str, "bridge", "encryption", "verification_levels", "send")
 	helper.Copy(up.Str, "bridge", "encryption", "verification_levels", "share")
diff --git a/example-config.yaml b/example-config.yaml
index fc988b4..d857f34 100644
--- a/example-config.yaml
+++ b/example-config.yaml
@@ -316,6 +316,8 @@ bridge:
         # This will cause the bridge bot to be in private chats for the encryption to work properly.
         # It is recommended to also set private_chat_portal_meta to true when using this.
         default: false
+        # Whether to use MSC2409/MSC3202 instead of /sync long polling for receiving encryption-related data.
+        appservice: false
         # Require encryption, drop any unencrypted messages.
         require: false
         # Enable key sharing? If enabled, key requests for rooms where users are in will be fulfilled.