diff --git a/js/xpconnect/src/Sandbox.cpp b/js/xpconnect/src/Sandbox.cpp
index 95e3ae02e530..c47f71c5bd6b 100644
--- a/js/xpconnect/src/Sandbox.cpp
+++ b/js/xpconnect/src/Sandbox.cpp
@@ -1843,7 +1843,7 @@ nsXPCComponents_utils_Sandbox::CallOrConstruct(nsIXPConnectWrappedNative* wrappe
 nsresult
 xpc::EvalInSandbox(JSContext* cx, HandleObject sandboxArg, const nsAString& source,
                    const nsACString& filename, int32_t lineNo,
-                   JSVersion jsVersion, MutableHandleValue rval)
+                   MutableHandleValue rval)
 {
     JS_AbortIfWrongThread(cx);
     rval.set(UndefinedValue());
diff --git a/js/xpconnect/src/XPCComponents.cpp b/js/xpconnect/src/XPCComponents.cpp
index d6d890070da9..cdc220596a7d 100644
--- a/js/xpconnect/src/XPCComponents.cpp
+++ b/js/xpconnect/src/XPCComponents.cpp
@@ -2211,24 +2211,7 @@ nsXPCComponents_Utils::EvalInSandbox(const nsAString& source,
     if (!JS_ValueToObject(cx, sandboxVal, &sandbox) || !sandbox)
         return NS_ERROR_INVALID_ARG;
 
-    // Optional third argument: JS version, as a string.
-    JSVersion jsVersion = JSVERSION_DEFAULT;
-    if (optionalArgc >= 1) {
-        JSString* jsVersionStr = ToString(cx, version);
-        if (!jsVersionStr)
-            return NS_ERROR_INVALID_ARG;
-
-        JSAutoByteString bytes(cx, jsVersionStr);
-        if (!bytes)
-            return NS_ERROR_INVALID_ARG;
-
-        // Treat non-default version designation as default.
-        if (JS_StringToVersion(bytes.ptr()) == JSVERSION_UNKNOWN &&
-            strcmp(bytes.ptr(), "latest"))
-        {
-            return NS_ERROR_INVALID_ARG;
-        }
-    }
+    // Optional third argument: JS version, as a string, is unused.
 
     // Optional fourth and fifth arguments: filename and line number.
     int32_t lineNo = (optionalArgc >= 3) ? lineNumber : 1;
@@ -2246,8 +2229,7 @@ nsXPCComponents_Utils::EvalInSandbox(const nsAString& source,
         }
     }
 
-    return xpc::EvalInSandbox(cx, sandbox, source, filename, lineNo,
-                              jsVersion, retval);
+    return xpc::EvalInSandbox(cx, sandbox, source, filename, lineNo, retval);
 }
 
 NS_IMETHODIMP
diff --git a/js/xpconnect/src/nsXPConnect.cpp b/js/xpconnect/src/nsXPConnect.cpp
index 93a7dcefc1fb..6a86161e55fa 100644
--- a/js/xpconnect/src/nsXPConnect.cpp
+++ b/js/xpconnect/src/nsXPConnect.cpp
@@ -798,8 +798,7 @@ nsXPConnect::EvalInSandboxObject(const nsAString& source, const char* filename,
     } else {
         filenameStr = NS_LITERAL_CSTRING("x-bogus://XPConnect/Sandbox");
     }
-    return EvalInSandbox(cx, sandbox, source, filenameStr, 1,
-                         JSVERSION_DEFAULT, rval);
+    return EvalInSandbox(cx, sandbox, source, filenameStr, 1, rval);
 }
 
 NS_IMETHODIMP
diff --git a/js/xpconnect/src/xpcprivate.h b/js/xpconnect/src/xpcprivate.h
index bddb262047fe..1504a1a67ac0 100644
--- a/js/xpconnect/src/xpcprivate.h
+++ b/js/xpconnect/src/xpcprivate.h
@@ -2916,7 +2916,7 @@ CreateSandboxObject(JSContext* cx, JS::MutableHandleValue vp, nsISupports* prinO
 nsresult
 EvalInSandbox(JSContext* cx, JS::HandleObject sandbox, const nsAString& source,
               const nsACString& filename, int32_t lineNo,
-              JSVersion jsVersion, JS::MutableHandleValue rval);
+              JS::MutableHandleValue rval);
 
 nsresult
 GetSandboxAddonId(JSContext* cx, JS::HandleObject sandboxArg,