diff --git a/Core/API/Parameter/StringType.class.php b/Core/API/Parameter/StringType.class.php
index 1916910..7732530 100644
--- a/Core/API/Parameter/StringType.class.php
+++ b/Core/API/Parameter/StringType.class.php
@@ -4,8 +4,10 @@ namespace Core\API\Parameter;
 
 class StringType extends Parameter {
 
+  const UNLIMITED = -1;
+
   public int $maxLength;
-  public function __construct(string $name, int $maxLength = -1, bool $optional = FALSE, ?string $defaultValue = NULL, ?array $choices = NULL) {
+  public function __construct(string $name, int $maxLength = self::UNLIMITED, bool $optional = FALSE, ?string $defaultValue = NULL, ?array $choices = NULL) {
     $this->maxLength = $maxLength;
     parent::__construct($name, Parameter::TYPE_STRING, $optional, $defaultValue, $choices);
   }
diff --git a/Core/API/SettingsAPI.class.php b/Core/API/SettingsAPI.class.php
index b44e5f2..703c5ce 100644
--- a/Core/API/SettingsAPI.class.php
+++ b/Core/API/SettingsAPI.class.php
@@ -37,28 +37,11 @@ namespace Core\API\Settings {
        $key = $this->getParam("key");
        $sql = $this->context->getSQL();
 
-       $query = $sql->select("name", "value") ->from("Settings");
-
-       if (!is_null($key)) {
-         $query->where(new CondRegex(new Column("name"), $key));
-       }
-
-       // filter sensitive values, if called from outside
-       if ($this->isExternalCall()) {
-         $query->where(new CondNot("private"));
-       }
-
-       $res = $query->execute();
-
-       $this->success = ($res !== FALSE);
-       $this->lastError = $sql->getLastError();
-
-       if ($this->success) {
-         $settings = array();
-         foreach($res as $row) {
-           $settings[$row["name"]] = $row["value"];
-         }
+       $settings = Settings::getAll($sql, $key);
+       if ($settings !== null) {
          $this->result["settings"] = $settings;
+       } else {
+         return $this->createError("Error fetching settings: " . $sql->getLastError());
        }
 
        return $this->success;
@@ -151,7 +134,7 @@ namespace Core\API\Settings {
       return null;
     }
 
-    private function deleteKeys(array $keys) {
+    private function deleteKeys(array $keys): bool {
       $sql = $this->context->getSQL();
       $res = $sql->delete("Settings")
         ->where(new CondIn(new Column("name"), $keys))
diff --git a/Core/Configuration/Settings.class.php b/Core/Configuration/Settings.class.php
index 8ccb847..89d4dab 100644
--- a/Core/Configuration/Settings.class.php
+++ b/Core/Configuration/Settings.class.php
@@ -7,7 +7,11 @@
 namespace Core\Configuration;
 
 use Core\Driver\Logger\Logger;
+use Core\Driver\SQL\Column\Column;
+use Core\Driver\SQL\Condition\CondNot;
+use Core\Driver\SQL\Condition\CondRegex;
 use Core\Driver\SQL\Query\Insert;
+use Core\Driver\SQL\SQL;
 use Core\Objects\Context;
 
 class Settings {
@@ -45,6 +49,41 @@ class Settings {
     $this->logger = new Logger("Settings");
   }
 
+  public static function getAll(?SQL $sql, ?string $pattern = null, bool $external = false): ?array {
+    $query = $sql->select("name", "value") ->from("Settings");
+
+    if ($pattern) {
+      $query->where(new CondRegex(new Column("name"), $pattern));
+    }
+
+    if ($external) {
+      $query->where(new CondNot("private"));
+    }
+
+    $res = $query->execute();
+    if ($res !== false && $res !== null) {
+      $settings = array();
+      foreach($res as $row) {
+        $settings[$row["name"]] = $row["value"];
+      }
+      return $settings;
+    } else {
+      return null;
+    }
+  }
+
+  public static function get(?SQL $sql, string $key, mixed $defaultValue): mixed {
+    $res = $sql->select("value") ->from("Settings")
+      ->whereEq("name", $key)
+      ->execute();
+
+    if ($res === false || $res === null) {
+      return null;
+    } else {
+      return (empty($res)) ? $defaultValue : $res[0]["value"];
+    }
+  }
+
   public function getJwtPublicKey(bool $allowPrivate = true): ?\Firebase\JWT\Key {
     if (empty($this->jwtPublicKey)) {
       if ($allowPrivate && $this->jwtSecretKey) {
diff --git a/Core/Driver/SQL/MySQL.class.php b/Core/Driver/SQL/MySQL.class.php
index 560f10a..bb7c055 100644
--- a/Core/Driver/SQL/MySQL.class.php
+++ b/Core/Driver/SQL/MySQL.class.php
@@ -201,7 +201,10 @@ class MySQL extends SQL {
         }
       }
     } catch (\mysqli_sql_exception $exception) {
-      $this->lastError = $this->logger->error("MySQL::execute failed: $stmt->error ($stmt->errno)");
+      $this->lastError = $this->logger->error("MySQL::execute failed: " .
+      ($stmt !== null
+        ? "$stmt->error ($stmt->errno)"
+        : $exception->getMessage()));
     } finally {
 
       if ($res !== null && !is_bool($res) && $fetchType !== self::FETCH_ITERATIVE) {
diff --git a/docker/php/Dockerfile b/docker/php/Dockerfile
index 2bc369d..460a438 100644
--- a/docker/php/Dockerfile
+++ b/docker/php/Dockerfile
@@ -1,13 +1,17 @@
 FROM composer:latest AS composer
-FROM php:8.0-fpm
+FROM php:8.1-fpm
 WORKDIR "/application"
+
+ARG ADDITIONAL_PACKAGES
+ARG ADDITIONAL_SCRIPT
+
 RUN mkdir -p /application/core/Configuration /var/www/.gnupg && \
     chown -R www-data:www-data /application /var/www/ && \
     chmod 700 /var/www/.gnupg
 
-# YAML + dev dependencies
+# YAML + dev dependencies + additional packages
 RUN apt-get update -y &&  \
-    apt-get install -y libyaml-dev libzip-dev libgmp-dev libpng-dev gnupg2 && \
+    apt-get install -y libyaml-dev libzip-dev libgmp-dev libpng-dev gnupg2 $ADDITIONAL_PACKAGES && \
     pecl install yaml && docker-php-ext-enable yaml && \
     docker-php-ext-install gd
 
@@ -27,5 +31,8 @@ RUN docker-php-ext-install mysqli zip gmp
 # clean cache
 RUN apt-get clean
 
+# run additional scripts
+RUN if [[ ! -z "$ADDITIONAL_SCRIPT" ]]; then $ADDITIONAL_SCRIPT; fi
+
 COPY --from=composer /usr/bin/composer /usr/bin/composer
 USER www-data
\ No newline at end of file