--- a/toolkit/components/telemetry/TelemetryEnvironment.jsm
+++ b/toolkit/components/telemetry/TelemetryEnvironment.jsm
@@ -418,17 +418,17 @@ function getWindowsVersionInfo() {
       {wSuiteMask: WORD},
       {wProductType: BYTE},
       {wReserved: BYTE}
       ]);
 
   let kernel32 = ctypes.open("kernel32");
   try {
     let GetVersionEx = kernel32.declare("GetVersionExW",
-                                        ctypes.default_abi,
+                                        ctypes.winapi_abi,
                                         BOOL,
                                         OSVERSIONINFOEXW.ptr);
     let winVer = OSVERSIONINFOEXW();
     winVer.dwOSVersionInfoSize = OSVERSIONINFOEXW.size;
 
     if (0 === GetVersionEx(winVer.address())) {
       throw ("Failure in GetVersionEx (returned 0)");
     }