diff --git a/caps/BasePrincipal.cpp b/caps/BasePrincipal.cpp
index b37209f53d77..c60fa2b15bf1 100644
--- a/caps/BasePrincipal.cpp
+++ b/caps/BasePrincipal.cpp
@@ -299,14 +299,6 @@ BasePrincipal::GetOriginSuffix(nsACString& aOriginAttributes)
   return mOriginSuffix->ToUTF8String(aOriginAttributes);
 }
 
-NS_IMETHODIMP
-BasePrincipal::GetAppStatus(uint16_t* aAppStatus)
-{
-  // TODO: Remove GetAppStatus.
-  *aAppStatus = nsIPrincipal::APP_STATUS_NOT_INSTALLED;
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 BasePrincipal::GetAppId(uint32_t* aAppId)
 {
diff --git a/caps/BasePrincipal.h b/caps/BasePrincipal.h
index 3f3c8344121b..0e07085d8216 100644
--- a/caps/BasePrincipal.h
+++ b/caps/BasePrincipal.h
@@ -63,8 +63,7 @@ public:
   NS_IMETHOD GetIsSystemPrincipal(bool* aResult) override;
   NS_IMETHOD GetOriginAttributes(JSContext* aCx, JS::MutableHandle<JS::Value> aVal) final;
   NS_IMETHOD GetOriginSuffix(nsACString& aOriginSuffix) final;
-  NS_IMETHOD GetAppStatus(uint16_t* aAppStatus) final;
-  NS_IMETHOD GetAppId(uint32_t* aAppStatus) final;
+  NS_IMETHOD GetAppId(uint32_t* aAppId) final;
   NS_IMETHOD GetIsInIsolatedMozBrowserElement(bool* aIsInIsolatedMozBrowserElement) final;
   NS_IMETHOD GetUnknownAppId(bool* aUnknownAppId) final;
   NS_IMETHOD GetUserContextId(uint32_t* aUserContextId) final;
diff --git a/caps/nsIPrincipal.idl b/caps/nsIPrincipal.idl
index 258aa384a9f5..afd4cac1630e 100644
--- a/caps/nsIPrincipal.idl
+++ b/caps/nsIPrincipal.idl
@@ -251,33 +251,6 @@ interface nsIPrincipal : nsISerializable
      */
     readonly attribute ACString baseDomain;
 
-    const short APP_STATUS_NOT_INSTALLED = 0;
-    const short APP_STATUS_INSTALLED     = 1;
-    const short APP_STATUS_PRIVILEGED    = 2;
-    const short APP_STATUS_CERTIFIED     = 3;
-
-    /**
-     * Gets the principal's app status, which indicates whether the principal
-     * corresponds to "app code", and if it does, how privileged that code is.
-     * This method returns one of the APP_STATUS constants above.
-     *
-     * Note that a principal may have
-     *
-     *   appId != nsIScriptSecurityManager::NO_APP_ID &&
-     *   appId != nsIScriptSecurityManager::UNKNOWN_APP_ID
-     *
-     * and still have appStatus == APP_STATUS_NOT_INSTALLED.  That's because
-     * appId identifies the app that contains this principal, but a window
-     * might be contained in an app and not be running code that the app has
-     * vouched for.  For example, the window might be inside an <iframe
-     * mozbrowser>, or the window's origin might not match the app's origin.
-     *
-     * If you're doing a check to determine "does this principal correspond to
-     * app code?", you must check appStatus; checking appId != NO_APP_ID is not
-     * sufficient.
-     */
-    [infallible] readonly attribute unsigned short appStatus;
-
     /**
      * Gets the id of the app this principal is inside.  If this principal is
      * not inside an app, returns nsIScriptSecurityManager::NO_APP_ID.
@@ -293,9 +266,6 @@ interface nsIPrincipal : nsISerializable
      * inside an app frame; in this case, the content inside the iframe should
      * not have any of the app's permissions, even if the iframe is at the same
      * origin as the app.
-     *
-     * If you're doing a security check based on appId, you must check
-     * appStatus as well.
      */
     [infallible] readonly attribute unsigned long appId;