diff --git a/application/controllers/ErrorController.php b/application/controllers/ErrorController.php
index df422d716..580015b25 100644
--- a/application/controllers/ErrorController.php
+++ b/application/controllers/ErrorController.php
@@ -21,7 +21,8 @@ class ErrorController extends ActionController
     /**
      * Regular expression to match exceptions resulting from missing functions/classes
      */
-    const MISSING_DEP_ERROR = "/Uncaught Error:.*(?:undefined function (\S+)|Class '([^']+)' not found).* in ([^:]+)/";
+    const MISSING_DEP_ERROR =
+        "/Uncaught Error:.*(?:undefined function (\S+)|Class ['\"]([^']+)['\"] not found).* in ([^:]+)/";
 
     /**
      * {@inheritdoc}
@@ -108,9 +109,10 @@ class ErrorController extends ActionController
                         }
                     }
 
-                    if (preg_match('/^(?:Icinga\\\Module\\\(\w+)|(\w+)\\\)/', $match[1] ?: $match[2], $natch)) {
+                    if (preg_match('/^(?:Icinga\\\Module\\\(\w+)|(\w+)\\\(\w+))/', $match[1] ?: $match[2], $natch)) {
                         $this->view->requiredModule = isset($natch[1]) ? strtolower($natch[1]) : null;
-                        $this->view->requiredLibrary = isset($natch[2]) ? $natch[2] : null;
+                        $this->view->requiredVendor = isset($natch[2]) ? $natch[2] : null;
+                        $this->view->requiredProject = isset($natch[3]) ? $natch[3] : null;
                     }
                 }
 
diff --git a/application/views/scripts/error/error.phtml b/application/views/scripts/error/error.phtml
index 51ad9143f..ecb1c2b48 100644
--- a/application/views/scripts/error/error.phtml
+++ b/application/views/scripts/error/error.phtml
@@ -16,42 +16,90 @@ if (isset($stackTraces)) {
         echo '<p tabindex="-1" class="autofocus error-message">' . nl2br($this->escape($message)) . '</p>';
     }
 }
+
+$libraries = \Icinga\Application\Icinga::app()->getLibraries();
+$coreReason = [];
+$modReason = [];
+
+if (isset($requiredVendor, $requiredProject) && $requiredVendor && $requiredProject) {
+    // TODO: I don't like this, can we define requirements somewhere else?
+    $coreDeps = ['icinga-php-library' => '>= 0.6', 'icinga-php-thirdparty' => '>= 0.10'];
+
+    foreach ($coreDeps as $libraryName => $requiredVersion) {
+        if (! $libraries->has($libraryName)) {
+            $coreReason[] = sprintf($this->translate(
+                'Library "%s" is required and missing. Please install a version of it matching the required one: %s'
+            ), $libraryName, $requiredVersion);
+        } elseif (! $libraries->has($libraryName, $requiredVersion) && $libraries->get($libraryName)->isRequired($requiredVendor, $requiredProject)) {
+            $coreReason[] = sprintf($this->translate(
+                'Library "%s" is required and installed, but its version (%s) does not satisfy the required one: %s'
+            ), $libraryName, $libraries->get($libraryName)->getVersion() ?: '-', $requiredVersion);
+        }
+    }
+
+    if (! empty($coreReason)) {
+        array_unshift($coreReason, $this->translate('You have unmet dependencies. Please check Icinga Web 2\'s installation instructions.'));
+    }
+}
+
+if (isset($module)) {
+    $manager = \Icinga\Application\Icinga::app()->getModuleManager();
+    if ($manager->hasUnmetDependencies($module->getName())) {
+        if (isset($requiredModule) && $requiredModule && isset($module->getRequiredModules()[$requiredModule])) {
+            if (! $manager->hasInstalled($requiredModule)) {
+                $modReason[] = sprintf($this->translate(
+                    'Module "%s" is required and missing. Please install a version of it matching the required one: %s'
+                ), $requiredModule, $module->getRequiredModules()[$requiredModule]);
+            } elseif (! $manager->hasEnabled($requiredModule)) {
+                $modReason[] = sprintf($this->translate(
+                    'Module "%s" is required and installed, but not enabled. Please enable module "%1$s".'
+                ), $requiredModule);
+            } elseif (! $manager->has($requiredModule, $module->getRequiredModules()[$requiredModule])) {
+                $modReason[] = sprintf($this->translate(
+                    'Module "%s" is required and installed, but its version (%s) does not satisfy the required one: %s'
+                ), $requiredModule, $manager->getModule($requiredModule, false)->getVersion(), $module->getRequiredModules()[$requiredModule]);
+            }
+        } elseif (isset($requiredVendor, $requiredProject) && $requiredVendor && $requiredProject) {
+            foreach ($module->getRequiredLibraries() as $libraryName => $requiredVersion) {
+                if (! $libraries->has($libraryName)) {
+                    $modReason[] = sprintf($this->translate(
+                        'Library "%s" is required and missing. Please install a version of it matching the required one: %s'
+                    ), $libraryName, $requiredVersion);
+                } elseif (! $libraries->has($libraryName, $requiredVersion) && $libraries->get($libraryName)->isRequired($requiredVendor, $requiredProject)) {
+                    $modReason[] = sprintf($this->translate(
+                        'Library "%s" is required and installed, but its version (%s) does not satisfy the required one: %s'
+                    ), $libraryName, $libraries->get($libraryName)->getVersion() ?: '-', $requiredVersion);
+                }
+            }
+        }
+
+        if (! empty($modReason)) {
+            array_unshift($modReason, sprintf($this->translate(
+                'This error might have occurred because module "%s" has unmet dependencies.'
+                . ' Please check it\'s installation instructions and install missing dependencies.'
+            ), $module->getName()));
+        }
+    }
+}
+
+// The following doesn't use ipl\Html because that's what the error possibly is about
 ?>
-<?php if (isset($module)): ?>
-  <?php $manager = \Icinga\Application\Icinga::app()->getModuleManager(); ?>
-  <?php if ($manager->hasUnmetDependencies($module->getName())): ?>
-    <div class="error-reason">
-        <p><?= sprintf($this->translate(
-            'This error might have occurred because module "%s" has unmet dependencies.'
-            . ' Please check it\'s installation instructions and install missing dependencies.'
-        ), $module->getName()) ?></p>
-    <?php if (isset($requiredModule) && $requiredModule && isset($module->getRequiredModules()[$requiredModule])): ?>
-      <?php if (! $manager->hasInstalled($requiredModule)): ?>
-        <p><?= sprintf($this->translate(
-            'Module "%s" is required and missing. Please install a version of it matching the required one: %s'
-        ), $requiredModule, $module->getRequiredModules()[$requiredModule]) ?></p>
-      <?php elseif (! $manager->hasEnabled($requiredModule)): ?>
-        <p><?= sprintf($this->translate(
-            'Module "%s" is required and installed, but not enabled. Please enable module "%1$s".'
-        ), $requiredModule) ?></p>
-      <?php elseif (! $manager->has($requiredModule, $module->getRequiredModules()[$requiredModule])): ?>
-        <p><?= sprintf($this->translate(
-            'Module "%s" is required and installed, but its version (%s) does not satisfy the required one: %s'
-        ), $requiredModule, $manager->getModule($requiredModule, false)->getVersion(), $module->getRequiredModules()[$requiredModule]) ?></p>
-      <?php endif ?>
-    <?php elseif (isset($requiredLibrary) && $requiredLibrary && isset($module->getRequiredLibraries()[$requiredLibrary])): ?>
-      <?php $libraries = \Icinga\Application\Icinga::app()->getLibraries(); ?>
-      <?php if (! $libraries->has($requiredLibrary)): ?>
-        <p><?= sprintf($this->translate(
-            'Library "%s" is required and missing. Please install a version of it matching the required one: %s'
-        ), $requiredLibrary, $module->getRequiredLibraries()[$requiredLibrary]) ?></p>
-      <?php elseif (! $libraries->has($requiredLibrary, $module->getRequiredLibraries()[$requiredLibrary])): ?>
-        <p><?= sprintf($this->translate(
-            'Library "%s" is required and installed, but its version (%s) does not satisfy the required one: %s'
-        ), $requiredLibrary, $libraries->get($requiredLibrary)->getVersion(), $module->getRequiredLibraries()[$requiredLibrary]) ?></p>
-      <?php endif ?>
-    <?php endif ?>
-    </div>
-  <?php endif ?>
+<?php if (! empty($coreReason)): ?>
+<div class="error-reason">
 <?php endif ?>
+<?php foreach ($coreReason as $msg): ?>
+    <p><?= $msg ?></p>
+<?php endforeach ?>
+<?php if (! empty($coreReason)): ?>
 </div>
+<?php endif ?>
+
+<?php if (! empty($modReason)): ?>
+<div class="error-reason">
+<?php endif ?>
+<?php foreach ($modReason as $msg): ?>
+    <p><?= $msg ?></p>
+<?php endforeach ?>
+<?php if (! empty($modReason)): ?>
+</div>
+<?php endif ?>
diff --git a/library/Icinga/Application/Libraries/Library.php b/library/Icinga/Application/Libraries/Library.php
index b2e359b57..ece5efaf5 100644
--- a/library/Icinga/Application/Libraries/Library.php
+++ b/library/Icinga/Application/Libraries/Library.php
@@ -119,6 +119,22 @@ class Library
         return $this->version;
     }
 
+    /**
+     * Check whether the given package is required
+     *
+     * @param string $vendor The vendor of the project
+     * @param string $project The project's name
+     *
+     * @return bool
+     */
+    public function isRequired($vendor, $project)
+    {
+        // Ensure the parts are lowercase and separated by dashes, not capital letters
+        $project = strtolower(join('-', preg_split('/\w(?=[A-Z])/', $project)));
+
+        return isset($this->metaData()['require'][strtolower($vendor) . '/' . $project]);
+    }
+
     /**
      * Get this library's JS assets
      *