diff --git a/library/Opus/Model2/Identifier.php b/library/Opus/Model2/Identifier.php
new file mode 100644
index 00000000..c2035405
--- /dev/null
+++ b/library/Opus/Model2/Identifier.php
@@ -0,0 +1,270 @@
+<?php
+
+/**
+ * This file is part of OPUS. The software OPUS has been originally developed
+ * at the University of Stuttgart with funding from the German Research Net,
+ * the Federal Department of Higher Education and Research and the Ministry
+ * of Science, Research and the Arts of the State of Baden-Wuerttemberg.
+ *
+ * OPUS 4 is a complete rewrite of the original OPUS software and was developed
+ * by the Stuttgart University Library, the Library Service Center
+ * Baden-Wuerttemberg, the North Rhine-Westphalian Library Service Center,
+ * the Cooperative Library Network Berlin-Brandenburg, the Saarland University
+ * and State Library, the Saxon State Library - Dresden State and University
+ * Library, the Bielefeld University Library and the University Library of
+ * Hamburg University of Technology with funding from the German Research
+ * Foundation and the European Regional Development Fund.
+ *
+ * LICENCE
+ * OPUS 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 2 of the Licence, or any later version.
+ * OPUS 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 OPUS; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * @copyright   Copyright (c) 2008-2018, OPUS 4 development team
+ * @license     http://www.gnu.org/licenses/gpl.html General Public Licens
+ */
+
+namespace Opus\Model2;
+
+use Doctrine\ORM\Mapping as ORM;
+
+use function array_search;
+use function substr;
+
+/**
+ * Domain model for document identifiers in the Opus framework
+ *
+ * @uses \Opus\Model2\\AbstractModel
+ *
+ * TODO DOI and URN functions have been removed, we still have to find a new solution where to implement that functions
+ *
+ * TODO desing issues - see below
+ * The OPUS 4 framework is mapping objects to database tables (ORM). All identifiers are stored in the same table. The
+ * table was extended with fields relevant only to DOI identifiers. In a pure object model it would make more sense to
+ * extend the basic Opus\Identifier class for specific identifier types to add fields and functionality. Those classes
+ * would then have to be mapped to different table, however they could also still be mapped to the same table. At some
+ * point this will have to be revisited. We need a consistent object model independent of how the data is stored in the
+ * end.
+ *
+ * @ORM\Entity
+ * @ORM\Table(name="document_identifiers",
+ *     indexes={
+ *         @ORM\Index(name="fk_document_identifiers_documents", columns={"document_id"}),
+ *         @ORM\Index(name="fk_document_identifiers_documents_type", columns={"document_id", "type"})
+ *     })
+ */
+class Identifier extends AbstractModel
+{
+    /**
+     * @ORM\Id
+     * @ORM\Column(type="integer")
+     * @ORM\GeneratedValue
+     *
+     * @var int
+     */
+    private $id;
+
+    // TODO: Mapping as one-to-many relation with a document
+    // The @var type should then be changed to Model2\Document instead of int
+    /**
+     * @ORM\Column(name="document_id", type="integer")
+     *
+     * @var int
+     */
+    private $document;
+
+    /**
+     * @ORM\Column(name="value", type="text")
+     *
+     * @var string
+     */
+    private $value;
+
+    /**
+     * @ORM\Column(name="type", type="string")
+     *
+     * @var string
+     */
+    private $type;
+
+    /**
+     * @ORM\Column(name="status", type="string", columnDefinition="ENUM('registered','verified')", nullable=true)
+     *
+     * @var string
+     */
+    private $status;
+
+    /**
+     * @ORM\Column(name="registration_ts", type="string", nullable=true)
+     *
+     * @var string
+     */
+    private $registrationTs;
+
+    /**
+     * Mapping between identifier type and field name.
+     *
+     * @var array
+     */
+    private static $identifierMapping = [
+        'Old'       => 'old',
+        'Serial'    => 'serial',
+        'Uuid'      => 'uuid',
+        'Isbn'      => 'isbn',
+        'Urn'       => 'urn',
+        'Doi'       => 'doi',
+        'Handle'    => 'handle',
+        'Url'       => 'url',
+        'Issn'      => 'issn',
+        'StdDoi'    => 'std-doi',
+        'CrisLink'  => 'cris-link',
+        'SplashUrl' => 'splash-url',
+        'Opus3'     => 'opus3-id',
+        'Opac'      => 'opac-id',
+        'Arxiv'     => 'arxiv',
+        'Pubmed'    => 'pmid',
+    ];
+
+    /**
+     * @return int
+     */
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    /**
+     * @param int $id
+     */
+    public function setId($id)
+    {
+        $this->id = $id;
+    }
+
+    /**
+     * @return int
+     */
+    public function getDocument()
+    {
+        return $this->document;
+    }
+
+    /**
+     * @param int $document
+     */
+    public function setDocument($document)
+    {
+        $this->document = $document;
+    }
+
+    /**
+     * @return string
+     */
+    public function getValue()
+    {
+        return $this->value;
+    }
+
+    /**
+     * @param string $value
+     */
+    public function setValue($value)
+    {
+        $this->value = $value;
+    }
+
+    /**
+     * @return string
+     */
+    public function getType()
+    {
+        return $this->type;
+    }
+
+    /**
+     * @param string $type
+     */
+    public function setType($type)
+    {
+        $this->type = $type;
+    }
+
+    /**
+     * @return string
+     */
+    public function getStatus()
+    {
+        return $this->status;
+    }
+
+    /**
+     * @param string $status
+     */
+    public function setStatus($status)
+    {
+        $this->status = $status;
+    }
+
+    /**
+     * @return string
+     */
+    public function getRegistrationTs()
+    {
+        return $this->registrationTs;
+    }
+
+    /**
+     * @param string $registrationTs
+     */
+    public function setRegistrationTs($registrationTs)
+    {
+        $this->registrationTs = $registrationTs;
+    }
+
+    /**
+     * Returns the relevant properties of the class
+     *
+     * @return array
+     */
+    protected static function describe()
+    {
+        return [
+            'Value',
+            'Type',
+            'Status',
+            'RegistrationTs',
+        ];
+    }
+
+    /**
+     * @param string $fieldname
+     * @return string
+     */
+    public static function getTypeForFieldname($fieldname)
+    {
+        return self::$identifierMapping[substr($fieldname, 10)];
+    }
+
+    /**
+     * @param string $type
+     * @return string
+     */
+    public static function getFieldnameForType($type)
+    {
+        return 'Identifier' . array_search($type, self::$identifierMapping);
+    }
+
+    /**
+     * @return string
+     */
+    public function getModelType()
+    {
+        return 'identifier';
+    }
+}
diff --git a/tests/Opus/IdentifierTest.php b/tests/Opus/IdentifierTest.php
index 1039a691..1a807d51 100644
--- a/tests/Opus/IdentifierTest.php
+++ b/tests/Opus/IdentifierTest.php
@@ -43,10 +43,10 @@
 use Opus\Document;
 use Opus\DocumentFinder;
 use Opus\Doi\Generator\DefaultGenerator;
-use Opus\Identifier;
 use Opus\Identifier\DoiAlreadyExistsException;
 use Opus\Identifier\UrnAlreadyExistsException;
 use Opus\Model\ModelException;
+use Opus\Model2\Identifier;
 use OpusTest\TestAsset\TestCase;
 use Zend_Config;
 use Zend_Exception;
@@ -197,6 +197,8 @@ public function testCreateUrnCollisionUsingAddIdentifierUrn()
 
     public function testIsValidDoiPositive()
     {
+        $this->markTestSkipped('TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model');
+
         $doi = new Identifier();
         $doi->setType('doi');
         $doi->setValue('12.3456/opustest-789');
@@ -205,6 +207,8 @@ public function testIsValidDoiPositive()
 
     public function testIsValidDoiNegative()
     {
+        $this->markTestSkipped('TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model');
+
         $doiValuesToProbe = [
             '10.000/äöüß-987',
             '10.000/opus~987',
@@ -221,6 +225,11 @@ public function testIsValidDoiNegative()
 
     public function testIsLocalDoiPositiveWithGeneratorClass()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         // adapt configuration to allow detection local DOIs
         $doiConfig = [
             'generatorClass' => DefaultGenerator::class,
@@ -235,6 +244,11 @@ public function testIsLocalDoiPositiveWithGeneratorClass()
 
     public function testIsLocalDoiPositiveWithGeneratorClassAndMissingPrefixShlash()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         // adapt configuration to allow detection local DOIs
         $doiConfig = [
             'generatorClass' => DefaultGenerator::class,
@@ -249,6 +263,11 @@ public function testIsLocalDoiPositiveWithGeneratorClassAndMissingPrefixShlash()
 
     public function testIsLocalDoiPositiveWithoutGeneratorClass()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         // adapt configuration to allow detection local DOIs
         $doiConfig = [
             'generatorClass' => '',
@@ -263,6 +282,11 @@ public function testIsLocalDoiPositiveWithoutGeneratorClass()
 
     public function testIsLocalDoiPositiveWithoutGeneratorClassAndMissingPrefixSlash()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         // adapt configuration to allow detection local DOIs
         $doiConfig = [
             'generatorClass' => '',
@@ -277,6 +301,11 @@ public function testIsLocalDoiPositiveWithoutGeneratorClassAndMissingPrefixSlash
 
     public function testIsLocalDoiNegativeWithGeneratorClass()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         // adapt configuration to allow detection local DOIs
         $doiConfig = [
             'generatorClass' => DefaultGenerator::class,
@@ -291,6 +320,11 @@ public function testIsLocalDoiNegativeWithGeneratorClass()
 
     public function testIsLocalDoiNegativeWithGeneratorClassAlt()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         // adapt configuration to allow detection local DOIs
         $doiConfig = [
             'generatorClass' => DefaultGenerator::class,
@@ -305,6 +339,11 @@ public function testIsLocalDoiNegativeWithGeneratorClassAlt()
 
     public function testIsLocalDoiNegativeWithMissingGeneratorClass()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         // adapt configuration to allow detection local DOIs
         $doiConfig = [
             'generatorClass' => 'Opus\Doi\Generator\MissingGenerator',
@@ -319,6 +358,11 @@ public function testIsLocalDoiNegativeWithMissingGeneratorClass()
 
     public function testIsLocalDoiNegativeWithoutGeneratorClass()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         // adapt configuration to allow detection local DOIs
         $doiConfig = [
             'generatorClass' => '',
@@ -333,6 +377,11 @@ public function testIsLocalDoiNegativeWithoutGeneratorClass()
 
     public function testIsLocalDoiNegativeWithoutPrefixAndWithoutGeneratorClass()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         // adapt configuration to allow detection local DOIs
         $doiConfig = [
             'generatorClass' => '',
@@ -347,6 +396,11 @@ public function testIsLocalDoiNegativeWithoutPrefixAndWithoutGeneratorClass()
 
     public function testIsLocalDoiNegativeWithoutPrefixAndWithGeneratorClass()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         // adapt configuration to allow detection local DOIs
         $doiConfig = [
             'generatorClass' => DefaultGenerator::class,
@@ -361,6 +415,11 @@ public function testIsLocalDoiNegativeWithoutPrefixAndWithGeneratorClass()
 
     public function testIsDoiUniquePositive()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         $doiConfig = [
             'generatorClass' => DefaultGenerator::class,
             'prefix'         => '12.3456/',
@@ -386,6 +445,11 @@ public function testIsDoiUniquePositive()
 
     public function testIsDoiUniqueNegative()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         $doiConfig = [
             'generatorClass' => DefaultGenerator::class,
             'prefix'         => '12.3456/',
@@ -422,6 +486,11 @@ public function testIsDoiUniqueNegative()
 
     public function testIsUrnUniquePositive()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         $doc1   = $this->createDocumentWithIdentifierUrn('urn:987654321');
         $doc1Id = $doc1->store();
 
@@ -442,6 +511,11 @@ public function testIsUrnUniquePositive()
 
     public function testIsUrnUniqueNegative()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         $doc1   = $this->createDocumentWithIdentifierUrn('urn:987654321');
         $doc1Id = $doc1->store();
 
@@ -519,6 +593,11 @@ private function adaptDoiConfiguration($doiConfig)
 
     public function testCheckDoiCollisionFalse()
     {
+        $this->markTestSkipped(
+            'TODO DOCTRINE Issue #187 - DOI and URN functions have been removed from the model.'
+            . ' Document model still uses the old opus identifier model'
+        );
+
         $doiConfig = [
             'generatorClass' => DefaultGenerator::class,
             'prefix'         => '12.3456/',