diff --git a/application/Espo/Core/Formula/Functions/ArrayGroup/JoinType.php b/application/Espo/Core/Formula/Functions/ArrayGroup/JoinType.php
new file mode 100644
index 0000000000..25a23e9c9b
--- /dev/null
+++ b/application/Espo/Core/Formula/Functions/ArrayGroup/JoinType.php
@@ -0,0 +1,59 @@
+<?php
+/************************************************************************
+ * This file is part of EspoCRM.
+ *
+ * EspoCRM - Open Source CRM application.
+ * Copyright (C) 2014-2021 Yurii Kuznietsov, Taras Machyshyn, Oleksii Avramenko
+ * Website: https://www.espocrm.com
+ *
+ * EspoCRM is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * EspoCRM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with EspoCRM. If not, see http://www.gnu.org/licenses/.
+ *
+ * The interactive user interfaces in modified source and object code versions
+ * of this program must display Appropriate Legal Notices, as required under
+ * Section 5 of the GNU General Public License version 3.
+ *
+ * In accordance with Section 7(b) of the GNU General Public License version 3,
+ * these Appropriate Legal Notices must retain the display of the "EspoCRM" word.
+ ************************************************************************/
+
+namespace Espo\Core\Formula\Functions\ArrayGroup;
+
+use Espo\Core\Formula\{
+    Functions\BaseFunction,
+    ArgumentList,
+};
+
+class JoinType extends BaseFunction
+{
+    public function process(ArgumentList $args)
+    {
+        if (count($args) < 2) {
+            $this->throwTooFewArguments();
+        }
+
+        $list = $this->evaluate($args[0]);
+
+        $separator = $this->evaluate($args[1]);
+
+        if (!is_string($separator)) {
+            $this->throwBadArgumentValue(2, 'string');
+        }
+
+        if (is_null($list)) {
+            return '';
+        }
+
+        return implode($separator, $list);
+    }
+}
diff --git a/tests/unit/Espo/Core/Formula/EvaluatorTest.php b/tests/unit/Espo/Core/Formula/EvaluatorTest.php
index 08b3b70142..938fa70da0 100644
--- a/tests/unit/Espo/Core/Formula/EvaluatorTest.php
+++ b/tests/unit/Espo/Core/Formula/EvaluatorTest.php
@@ -29,8 +29,6 @@
 
 namespace tests\unit\Espo\Core\Formula;
 
-use Espo\ORM\Entity;
-
 use Espo\Core\Formula\Evaluator;
 use Espo\Core\InjectableFactory;
 
@@ -183,6 +181,17 @@ class EvaluatorTest extends \PHPUnit\Framework\TestCase
         $this->assertEquals(4, $actual);
     }
 
+    public function testArrayJoin()
+    {
+        $expression = "array\\join(list('0', '1'), '-')";
+
+        $expected = '0-1';
+
+        $actual = $this->evaluator->process($expression);
+
+        $this->assertEquals($expected, $actual);
+    }
+
     public function testWhile()
     {
         $expression = "