diff --git a/core/Api/GroupsAPI.class.php b/core/Api/GroupsAPI.class.php
index 611705b..803eb44 100644
--- a/core/Api/GroupsAPI.class.php
+++ b/core/Api/GroupsAPI.class.php
@@ -177,8 +177,11 @@ namespace Api\Groups {
       }
 
       $id = $this->getParam("uid");
-      $sql = $this->user->getSQL();
+      if (in_array($id, DEFAULT_GROUPS)) {
+        return $this->createError("You cannot delete a default group.");
+      }
 
+      $sql = $this->user->getSQL();
       $res = $sql->select($sql->count())
         ->from("Group")
         ->where(new Compare("uid", $id))
diff --git a/core/Api/RoutesAPI.class.php b/core/Api/RoutesAPI.class.php
index 9adda89..8be140f 100644
--- a/core/Api/RoutesAPI.class.php
+++ b/core/Api/RoutesAPI.class.php
@@ -26,7 +26,7 @@ namespace Api\Routes {
   use Api\RoutesAPI;
   use Driver\SQL\Column\Column;
   use Driver\SQL\Condition\CondBool;
-  use Driver\SQL\Condition\Regex;
+  use Driver\SQL\Condition\CondRegex;
 
   class Fetch extends RoutesAPI {
 
@@ -99,7 +99,7 @@ namespace Api\Routes {
         ->select("uid", "request", "action", "target", "extra")
         ->from("Route")
         ->where(new CondBool("active"))
-        ->where(new Regex($request, new Column("request")))
+        ->where(new CondRegex($request, new Column("request")))
         ->limit(1)
         ->execute();
 
diff --git a/core/Driver/SQL/Condition/CondIn.class.php b/core/Driver/SQL/Condition/CondIn.class.php
index f46f350..f0598fe 100644
--- a/core/Driver/SQL/Condition/CondIn.class.php
+++ b/core/Driver/SQL/Condition/CondIn.class.php
@@ -2,8 +2,6 @@
 
 namespace Driver\SQL\Condition;
 
-use Driver\SQL\Column\Column;
-
 class CondIn extends Condition {
 
   private string $column;
diff --git a/core/Driver/SQL/Condition/Regex.class.php b/core/Driver/SQL/Condition/CondKeyword.class.php
similarity index 57%
rename from core/Driver/SQL/Condition/Regex.class.php
rename to core/Driver/SQL/Condition/CondKeyword.class.php
index f0ba2bf..a153da6 100644
--- a/core/Driver/SQL/Condition/Regex.class.php
+++ b/core/Driver/SQL/Condition/CondKeyword.class.php
@@ -2,16 +2,19 @@
 
 namespace Driver\SQL\Condition;
 
-class Regex extends Condition {
+abstract class CondKeyword extends Condition {
 
   private $leftExpression;
   private $rightExpression;
+  private string $keyword;
 
-  public function __construct($leftExpression, $rightExpression) {
+  public function __construct($keyword, $leftExpression, $rightExpression) {
     $this->leftExpression = $leftExpression;
     $this->rightExpression = $rightExpression;
+    $this->keyword = $keyword;
   }
 
   public function getLeftExp() { return $this->leftExpression; }
   public function getRightExp() { return $this->rightExpression; }
+  public function getKeyword() { return $this->keyword; }
 }
\ No newline at end of file
diff --git a/core/Driver/SQL/Condition/CondLike.class.php b/core/Driver/SQL/Condition/CondLike.class.php
new file mode 100644
index 0000000..1e7b949
--- /dev/null
+++ b/core/Driver/SQL/Condition/CondLike.class.php
@@ -0,0 +1,10 @@
+<?php
+
+namespace Driver\SQL\Condition;
+
+class CondLike extends CondKeyword {
+
+  public function __construct($leftExpression, $rightExpression) {
+    parent::__construct("LIKE", $leftExpression, $rightExpression);
+  }
+}
\ No newline at end of file
diff --git a/core/Driver/SQL/Condition/CondRegex.class.php b/core/Driver/SQL/Condition/CondRegex.class.php
new file mode 100644
index 0000000..1147bce
--- /dev/null
+++ b/core/Driver/SQL/Condition/CondRegex.class.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace Driver\SQL\Condition;
+
+class CondRegex extends CondKeyword {
+
+  public function __construct($leftExpression, $rightExpression) {
+    parent::__construct("REGEXP", $leftExpression, $rightExpression);
+  }
+
+}
\ No newline at end of file
diff --git a/core/Driver/SQL/MySQL.class.php b/core/Driver/SQL/MySQL.class.php
index bf63a61..0f418e1 100644
--- a/core/Driver/SQL/MySQL.class.php
+++ b/core/Driver/SQL/MySQL.class.php
@@ -13,7 +13,7 @@ use \Driver\SQL\Column\DateTimeColumn;
 use Driver\SQL\Column\BoolColumn;
 use Driver\SQL\Column\JsonColumn;
 
-use Driver\SQL\Condition\Regex;
+use Driver\SQL\Condition\CondRegex;
 use Driver\SQL\Expression\Add;
 use Driver\SQL\Strategy\Strategy;
 use \Driver\SQL\Strategy\UpdateStrategy;
@@ -304,16 +304,4 @@ class MySQL extends SQL {
   public function getStatus() {
     return mysqli_stat($this->connection);
   }
-
-  protected function buildCondition($condition, &$params) {
-    if($condition instanceof Regex) {
-      $left = $condition->getLeftExp();
-      $right = $condition->getRightExp();
-      $left = ($left instanceof Column) ? $this->columnName($left->getName()) : $this->addValue($left, $params);
-      $right = ($right instanceof Column) ? $this->columnName($right->getName()) : $this->addValue($right, $params);
-      return $left . " REGEXP " . $right;
-    } else {
-      return parent::buildCondition($condition, $params);
-    }
-  }
 }
diff --git a/core/Driver/SQL/PostgreSQL.class.php b/core/Driver/SQL/PostgreSQL.class.php
index 9b5e988..0f5895d 100644
--- a/core/Driver/SQL/PostgreSQL.class.php
+++ b/core/Driver/SQL/PostgreSQL.class.php
@@ -13,7 +13,7 @@ use \Driver\SQL\Column\DateTimeColumn;
 use Driver\SQL\Column\BoolColumn;
 use Driver\SQL\Column\JsonColumn;
 
-use Driver\SQL\Condition\Regex;
+use Driver\SQL\Condition\CondRegex;
 use Driver\SQL\Expression\Add;
 use Driver\SQL\Strategy\Strategy;
 use Driver\SQL\Strategy\UpdateStrategy;
@@ -304,7 +304,7 @@ class PostgreSQL extends SQL {
   }
 
   protected function buildCondition($condition, &$params) {
-    if($condition instanceof Regex) {
+    if($condition instanceof CondRegex) {
       $left = $condition->getLeftExp();
       $right = $condition->getRightExp();
       $left = ($left instanceof Column) ? $this->columnName($left->getName()) : $this->addValue($left, $params);
diff --git a/core/Driver/SQL/SQL.class.php b/core/Driver/SQL/SQL.class.php
index 2404ed2..ac86739 100644
--- a/core/Driver/SQL/SQL.class.php
+++ b/core/Driver/SQL/SQL.class.php
@@ -6,8 +6,9 @@ use Driver\SQL\Column\Column;
 use Driver\SQL\Condition\Compare;
 use Driver\SQL\Condition\CondBool;
 use Driver\SQL\Condition\CondIn;
+use Driver\SQL\Condition\CondKeyword;
 use Driver\SQL\Condition\CondOr;
-use Driver\SQL\Condition\Regex;
+use Driver\SQL\Condition\CondRegex;
 use Driver\SQL\Constraint\Constraint;
 use \Driver\SQL\Constraint\Unique;
 use \Driver\SQL\Constraint\PrimaryKey;
@@ -343,6 +344,13 @@ abstract class SQL {
 
       $values = implode(",", $values);
       return $this->columnName($condition->getColumn()) . " IN ($values)";
+    } else if($condition instanceof CondKeyword) {
+      $left = $condition->getLeftExp();
+      $right = $condition->getRightExp();
+      $keyword = $condition->getKeyword();
+      $left = ($left instanceof Column) ? $this->columnName($left->getName()) : $this->addValue($left, $params);
+      $right = ($right instanceof Column) ? $this->columnName($right->getName()) : $this->addValue($right, $params);
+      return "$left $keyword $right ";
     } else {
       $this->lastError = "Unsupported condition type: " . get_class($condition);
       return false;
diff --git a/core/constants.php b/core/constants.php
index b752eb6..6989e62 100644
--- a/core/constants.php
+++ b/core/constants.php
@@ -7,6 +7,10 @@ const USER_GROUP_SUPPORT_NAME = "Support";
 const USER_GROUP_ADMIN = 3;
 const USER_GROUP_ADMIN_NAME = "Administrator";
 
+const DEFAULT_GROUPS = array(
+  USER_GROUP_MODERATOR, USER_GROUP_SUPPORT, USER_GROUP_ADMIN
+);
+
 function GroupName($index) {
   $groupNames = array(
     USER_GROUP_MODERATOR => USER_GROUP_MODERATOR_NAME,
diff --git a/core/datetime.php b/core/datetime.php
index c09cefc..377c1bc 100644
--- a/core/datetime.php
+++ b/core/datetime.php
@@ -1,26 +1,5 @@
 <?php
 
-function setTimezone($default) {
-  $timezone = "";
-  if (is_link("/etc/localtime")) {
-    $filename = readlink("/etc/localtime");
-    $pos = strpos($filename, "zoneinfo");
-    if ($pos) {
-      $timezone = substr($filename, $pos + strlen("zoneinfo/"));
-    } else {
-      $timezone = $default;
-    }
-  } else {
-    $timezone = file_get_contents("/etc/timezone");
-    if (!strlen($timezone)) {
-      $timezone = $default;
-    }
-  }
-  date_default_timezone_set($timezone);
-}
-
-setTimezone("UTC");
-
 function getFirstWeekDayOfMonth($d = NULL) {
   if(is_null($d)) $d = date('Y-m-d H:i:s');
   $dt = new DateTime($d);