diff --git a/lib/utils/entity-text.js b/lib/utils/entity-text.js
--- a/lib/utils/entity-text.js
+++ b/lib/utils/entity-text.js
@@ -365,7 +365,7 @@
 type RenderFunctions = {
   +renderText: ({ +text: string }) => React.Node,
   +renderThread: ({ +id: string, +name: string }) => React.Node,
-  +renderUser: ({ +userID: string, usernameText: string }) => React.Node,
+  +renderUser: ({ +userID: string, +usernameText: string }) => React.Node,
   +renderColor: ({ +hex: string }) => React.Node,
 };
 function entityTextToReact(
diff --git a/native/chat/inner-robotext-message.react.js b/native/chat/inner-robotext-message.react.js
--- a/native/chat/inner-robotext-message.react.js
+++ b/native/chat/inner-robotext-message.react.js
@@ -120,8 +120,8 @@
 }
 
 type UserEntityProps = {
-  userID: string,
-  usernameText: string,
+  +userID: string,
+  +usernameText: string,
 };
 function UserEntity(props: UserEntityProps) {
   const { userID, usernameText } = props;
diff --git a/web/chat/robotext-message.react.js b/web/chat/robotext-message.react.js
--- a/web/chat/robotext-message.react.js
+++ b/web/chat/robotext-message.react.js
@@ -140,8 +140,8 @@
 );
 
 type UserEntityProps = {
-  userID: string,
-  usernameText: string,
+  +userID: string,
+  +usernameText: string,
 };
 
 function UserEntity(props: UserEntityProps) {