diff --git a/mingw-w64-headers/include/psapi.h b/mingw-w64-headers/include/psapi.h
index f38db4b..495874a 100644
--- a/mingw-w64-headers/include/psapi.h
+++ b/mingw-w64-headers/include/psapi.h
@@ -140,7 +140,26 @@
   DWORD dwFilterFlag
 );
 
-#if (_WIN32_WINNT >= 0x0600)
+typedef union _PSAPI_WORKING_SET_BLOCK {
+  ULONG_PTR Flags;
+  __C89_NAMELESS struct {
+    ULONG_PTR Protection  :5;
+    ULONG_PTR ShareCount  :3;
+    ULONG_PTR Shared  :1;
+    ULONG_PTR Reserved  :3;
+#ifdef _WIN64
+    ULONG_PTR VirtualPage  :52;
+#else
+    ULONG_PTR VirtualPage  :20;
+#endif
+  } ;
+} PSAPI_WORKING_SET_BLOCK, *PPSAPI_WORKING_SET_BLOCK;
+
+typedef struct _PSAPI_WORKING_SET_INFORMATION {
+  ULONG_PTR               NumberOfEntries;
+  PSAPI_WORKING_SET_BLOCK WorkingSetInfo[1];
+} PSAPI_WORKING_SET_INFORMATION, *PPSAPI_WORKING_SET_INFORMATION;
+
 typedef union _PSAPI_WORKING_SET_EX_BLOCK {
   ULONG_PTR Flags;
   __C89_NAMELESS struct {
@@ -159,8 +178,6 @@
   PSAPI_WORKING_SET_EX_BLOCK VirtualAttributes;
 } PSAPI_WORKING_SET_EX_INFORMATION, *PPSAPI_WORKING_SET_EX_INFORMATION;
 
-#endif /*(_WIN32_WINNT >= 0x0600)*/
-
 #ifdef __cplusplus
 }
 #endif