--- a/install.php
+++ b/install.php
@@ -19,6 +19,8 @@
     }
     $before=json_decode(IPS_GetConfiguration($manager),true,128,JSON_THROW_ON_ERROR);
     $report['files']=v4StageInstall(__DIR__,'/var/lib/symcon/modules/Enelix-EMS');
+    require_once __DIR__.'/installed_capture_bootstrap.php';
+    $report['classLoading']=v4ApplicationLoadInstalledCapture('/var/lib/symcon/modules/Enelix-EMS',__DIR__.'/MANIFEST.json');
     $controls=[];
     foreach (IPS_GetModuleList() as $mid) if ((IPS_GetModule($mid)['Prefix']??'')==='MC') $controls=array_merge($controls,IPS_GetInstanceListByModuleID($mid));
     if (count($controls)!==1||!function_exists('MC_ReloadModule')) throw new RuntimeException('Module Control nicht eindeutig.');
@@ -38,7 +40,7 @@
         $marker=$dir.'/observer-import.json';
         if (!is_file($marker)&&!IPS_GetProperty($manager,'NetzfahrplanV4MessdatenAktiv')) {
             if (glob($dir.'/raw-*.jsonl')!==[]) throw new RuntimeException('Messdaten ohne Importabschluss vorhanden; nicht doppelt importieren.');
-            require_once __DIR__.'/source/libs/NetzfahrplanV4Messaufnahme.php';
+            // Reuse the hash-checked installed class; never load the staged copy.
             $count=0;$last=0;$cutoff=time()-172800;
             $files=glob('/srv/agent/netplan-v4-separated-observer-stage/data/raw-*.jsonl');sort($files,SORT_STRING);
             foreach ($files as $file) {
--- /dev/null
+++ b/installed_capture_bootstrap.php
@@ -0,0 +1,48 @@
+<?php
+
+declare(strict_types=1);
+
+/** Installer-only bootstrap. Load the same files the installed Manager uses.
+ * No IPS calls, source edits, state changes, or autoload of an unknown class.
+ */
+function v4ApplicationLoadInstalledCapture(string $target, string $manifestFile): array
+{
+    if (is_link($target) || realpath($target) !== $target || !is_dir($target)) {
+        throw new RuntimeException('Unerwartetes Modulverzeichnis.');
+    }
+    $manifest = json_decode((string) file_get_contents($manifestFile), true, 64, JSON_THROW_ON_ERROR);
+    if (($manifest['mode'] ?? null) !== 'data_application_only') {
+        throw new RuntimeException('Unerwarteter Installationsumfang.');
+    }
+    $classes = [
+        'Belevo\\EnelixEMS\\NetzfahrplanV4Bilanzierung' => 'libs/NetzfahrplanV4Bilanzierung.php',
+        'Belevo\\EnelixEMS\\NetzfahrplanV4Messaufnahme' => 'libs/NetzfahrplanV4Messaufnahme.php',
+    ];
+    // Check BOTH origins before loading either file, including the transitive dependency.
+    foreach ($classes as $class => $relative) {
+        $path = $target . '/' . $relative;
+        $expected = $manifest['files'][$relative]['after'] ?? null;
+        if (!is_string($expected) || !preg_match('/^[a-f0-9]{64}$/D', $expected)
+            || is_link($path) || !is_file($path) || realpath($path) !== $path
+            || hash_file('sha256', $path) !== $expected) {
+            throw new RuntimeException('Installierte Messbibliothek weicht vom geprueften Paket ab: ' . $relative);
+        }
+        if (class_exists($class, false)) {
+            $origin = (new ReflectionClass($class))->getFileName();
+            if ($origin !== $path) {
+                throw new RuntimeException('Messbibliothek bereits aus anderem Pfad geladen. Installationsaufruf separat ausfuehren, ohne weitere Sammler-Includes.');
+            }
+        }
+    }
+    foreach ($classes as $class => $relative) {
+        $path = $target . '/' . $relative;
+        if (!class_exists($class, false)) {
+            require_once $path;
+        }
+        if (!class_exists($class, false) || (new ReflectionClass($class))->getFileName() !== $path) {
+            throw new RuntimeException('Installierte Messbibliothek konnte nicht eindeutig geladen werden.');
+        }
+    }
+    return ['source' => 'installed_module_only', 'stagedClassesLoaded' => false,
+        'files' => array_values($classes)];
+}