diff --git a/addons/common/XEH_postInit.sqf b/addons/common/XEH_postInit.sqf
index 53de6b5d69..1c9155b3a2 100644
--- a/addons/common/XEH_postInit.sqf
+++ b/addons/common/XEH_postInit.sqf
@@ -84,6 +84,7 @@ if(!isServer) then {
 ["SEH_s", FUNC(_handleRequestSyncedEvent)] call FUNC(addEventHandler);
 [FUNC(syncedEventPFH), 0.5, []] call cba_fnc_addPerFrameHandler;
 
+call FUNC(checkFiles);
 
 /***************************************************************/
 /***************************************************************/
@@ -250,14 +251,3 @@ if(isMultiplayer && { time > 0 || isNull player } ) then {
         };
     }, 0, []] call cba_fnc_addPerFrameHandler;
 };
-
-// check dlls
-{
-    if (_x callExtension "version" == "") then {
-        private "_errorMsg";
-        _errorMsg = format ["Extension %1.dll not installed.", _x];
-
-        diag_log text format ["[ACE] ERROR: %1", _errorMsg];
-        ["[ACE] ERROR", _errorMsg, {findDisplay 46 closeDisplay 0}] call FUNC(errorMessage);
-    };
-} forEach getArray (configFile >> "ACE_Extensions" >> "extensions");
diff --git a/addons/common/XEH_preInit.sqf b/addons/common/XEH_preInit.sqf
index 54a5118cb0..5c2ad1e592 100644
--- a/addons/common/XEH_preInit.sqf
+++ b/addons/common/XEH_preInit.sqf
@@ -21,6 +21,7 @@ PREP(canInteract);
 PREP(canInteractWith);
 PREP(canUseWeapon);
 PREP(changeProjectileDirection);
+PREP(checkFiles);
 PREP(checkPBOs);
 PREP(claim);
 PREP(closeDialogIfTargetMoves);
diff --git a/addons/common/functions/fnc_checkFiles.sqf b/addons/common/functions/fnc_checkFiles.sqf
new file mode 100644
index 0000000000..868882151d
--- /dev/null
+++ b/addons/common/functions/fnc_checkFiles.sqf
@@ -0,0 +1,59 @@
+/*
+ * Author: commy2
+ *
+ * Compares version numbers of PBOs and DLLs.
+ *
+ * Argument:
+ * 0: Mode (Number)
+ *
+ * Return value:
+ * None.
+ */
+#include "script_component.hpp"
+
+///////////////
+// check addons
+///////////////
+private "_version";
+_version = getText (configFile >> "CfgPatches" >> "ace_main" >> "versionStr");
+
+diag_log text format ["[ACE]: ACE is version %1", _version]; ///////////////////////////////////////////////////////////////////////////
+
+private ["_addons", "_index"];
+
+_addons = activatedAddons;
+
+// speed up search. all ace pbos are loaded after ace_main.
+_index = _addons find "ace_main";
+reverse _addons; 
+_addons resize (count _addons - _index);
+_addons = [_addons, {_this find "ace_" == 0}] call FUNC(filter);
+
+{
+    if (getText (configFile >> "CfgPatches" >> _x >> "versionStr") != _version) then {
+        private "_errorMsg";
+        _errorMsg = format ["File %1.pbo is outdated.", _x];
+
+        diag_log text format ["[ACE] ERROR: %1", _errorMsg];
+
+        if (hasInterface) then {
+            ["[ACE] ERROR", _errorMsg, {findDisplay 46 closeDisplay 0}] call FUNC(errorMessage);
+        };
+    };
+} forEach _addons;
+
+///////////////
+// check dlls
+///////////////
+{
+    if (_x callExtension "version" == "") then {
+        private "_errorMsg";
+        _errorMsg = format ["Extension %1.dll not installed.", _x];
+
+        diag_log text format ["[ACE] ERROR: %1", _errorMsg];
+
+        if (hasInterface) then {
+            ["[ACE] ERROR", _errorMsg, {findDisplay 46 closeDisplay 0}] call FUNC(errorMessage);
+        };
+    };
+} forEach getArray (configFile >> "ACE_Extensions" >> "extensions");