diff --git a/Classes/Update/AddSites/AbstractSiteUpgrade.php b/Classes/Update/AddSites/AbstractSiteUpgrade.php
new file mode 100644
index 00000000..07930c12
--- /dev/null
+++ b/Classes/Update/AddSites/AbstractSiteUpgrade.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace In2code\Lux\Update\AddSites;
+
+use In2code\Lux\Domain\Service\SiteService;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
+
+abstract class AbstractSiteUpgrade
+{
+    /**
+     * [
+     *      123 => 'site 1',
+     *      124 => 'site 2',
+     * ]
+     *
+     * @var array
+     */
+    protected array $mapping = [];
+    protected SiteService $siteService;
+
+    public function __construct()
+    {
+        $this->siteService = GeneralUtility::makeInstance(SiteService::class);
+    }
+
+    protected function getSiteIdentifierFromPage(int $pageIdentifier): string
+    {
+        if (array_key_exists($pageIdentifier, $this->mapping)) {
+            return $this->mapping[$pageIdentifier];
+        }
+        $site = $this->siteService->getSiteFromPageIdentifier($pageIdentifier);
+        $siteIdentifier = $site->getIdentifier();
+        $this->mapping[$pageIdentifier] = $siteIdentifier;
+        return $siteIdentifier;
+    }
+}
diff --git a/Classes/Update/AddSites/AddSitesForDownloads.php b/Classes/Update/AddSites/AddSitesForDownloads.php
new file mode 100644
index 00000000..475402db
--- /dev/null
+++ b/Classes/Update/AddSites/AddSitesForDownloads.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace In2code\Lux\Update\AddSites;
+
+use In2code\Lux\Domain\Model\Download;
+use In2code\Lux\Utility\DatabaseUtility;
+
+class AddSitesForDownloads extends AbstractSiteUpgrade
+{
+    public function run(): void
+    {
+        $connection = DatabaseUtility::getConnectionForTable(Download::TABLE_NAME);
+        $records = $connection
+            ->executeQuery('select * from ' . Download::TABLE_NAME . ' where deleted=0')
+            ->fetchAllAssociative();
+        foreach ($records as $record) {
+            $siteIdentifier = $this->getSiteIdentifierFromPage($record['page']);
+            $connection->executeQuery(
+                'update ' . Download::TABLE_NAME . ' set site = "' . $siteIdentifier . '" where uid=' . $record['uid']
+            );
+        }
+    }
+}
diff --git a/Classes/Update/AddSites/AddSitesForLinkclick.php b/Classes/Update/AddSites/AddSitesForLinkclick.php
new file mode 100644
index 00000000..240f61d2
--- /dev/null
+++ b/Classes/Update/AddSites/AddSitesForLinkclick.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace In2code\Lux\Update\AddSites;
+
+use In2code\Lux\Domain\Model\Linkclick;
+use In2code\Lux\Utility\DatabaseUtility;
+
+class AddSitesForLinkclick extends AbstractSiteUpgrade
+{
+    public function run(): void
+    {
+        $connection = DatabaseUtility::getConnectionForTable(Linkclick::TABLE_NAME);
+        $records = $connection
+            ->executeQuery('select * from ' . Linkclick::TABLE_NAME . ' where deleted=0')
+            ->fetchAllAssociative();
+        foreach ($records as $record) {
+            $siteIdentifier = $this->getSiteIdentifierFromPage($record['page']);
+            $connection->executeQuery(
+                'update ' . Linkclick::TABLE_NAME . ' set site = "' . $siteIdentifier . '" where uid=' . $record['uid']
+            );
+        }
+    }
+}
diff --git a/Classes/Update/AddSites/AddSitesForPagevisits.php b/Classes/Update/AddSites/AddSitesForPagevisits.php
new file mode 100644
index 00000000..9844d220
--- /dev/null
+++ b/Classes/Update/AddSites/AddSitesForPagevisits.php
@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace In2code\Lux\Update\AddSites;
+
+use In2code\Lux\Domain\Model\Pagevisit;
+use In2code\Lux\Utility\DatabaseUtility;
+
+class AddSitesForPagevisits extends AbstractSiteUpgrade
+{
+    public function run(): void
+    {
+        $connection = DatabaseUtility::getConnectionForTable(Pagevisit::TABLE_NAME);
+        $records = $connection
+            ->executeQuery('select * from ' . Pagevisit::TABLE_NAME . ' where deleted=0')
+            ->fetchAllAssociative();
+        foreach ($records as $record) {
+            $siteIdentifier = $this->getSiteIdentifierFromPage($record['page']);
+            $connection->executeQuery(
+                'update ' . Pagevisit::TABLE_NAME . ' set site = "' . $siteIdentifier . '" where uid=' . $record['uid']
+            );
+        }
+    }
+}
diff --git a/Classes/Update/AddSitesUpgradeWizard.php b/Classes/Update/AddSitesUpgradeWizard.php
new file mode 100644
index 00000000..a909b0ed
--- /dev/null
+++ b/Classes/Update/AddSitesUpgradeWizard.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+namespace In2code\Lux\Update;
+
+use In2code\Lux\Domain\Model\Pagevisit;
+use In2code\Lux\Update\AddSites\AddSitesForDownloads;
+use In2code\Lux\Update\AddSites\AddSitesForPagevisits;
+use In2code\Lux\Update\AddSites\AddSitesForLinkclick;
+use In2code\Lux\Utility\DatabaseUtility;
+use Throwable;
+use TYPO3\CMS\Core\Utility\GeneralUtility;
+use TYPO3\CMS\Install\Attribute\UpgradeWizard;
+use TYPO3\CMS\Install\Updates\DatabaseUpdatedPrerequisite;
+use TYPO3\CMS\Install\Updates\UpgradeWizardInterface;
+
+#[UpgradeWizard('addSitesUpgradeWizard')]
+class AddSitesUpgradeWizard implements UpgradeWizardInterface
+{
+    public function getIdentifier(): string
+    {
+        return 'addSitesUpgradeWizard';
+    }
+
+    public function getTitle(): string
+    {
+        return 'LUX: Add sites to existing pagevisit records for multiclient functionality';
+    }
+
+    public function getDescription(): string
+    {
+        return 'Fill some database fields with information about sites';
+    }
+
+    public function executeUpdate(): bool
+    {
+        try {
+//            GeneralUtility::makeInstance(AddSitesForPagevisits::class)->run();
+//            GeneralUtility::makeInstance(AddSitesForDownloads::class)->run();
+            GeneralUtility::makeInstance(AddSitesForLinkclick::class)->run();
+        } catch (Throwable $exception) {
+            return false;
+        }
+        return true;
+    }
+
+    public function updateNecessary(): bool
+    {
+        return DatabaseUtility::isFieldExistingInTable('site', Pagevisit::TABLE_NAME)
+            && DatabaseUtility::isAnyFieldFilledInTable('site', Pagevisit::TABLE_NAME) === false;
+    }
+
+    public function getPrerequisites(): array
+    {
+        return [
+            DatabaseUpdatedPrerequisite::class,
+        ];
+    }
+}
diff --git a/Classes/Utility/DatabaseUtility.php b/Classes/Utility/DatabaseUtility.php
index 6021e54d..e7c92587 100644
--- a/Classes/Utility/DatabaseUtility.php
+++ b/Classes/Utility/DatabaseUtility.php
@@ -97,4 +97,22 @@ public static function isFieldInTableFilled(string $fieldName, string $tableName
             ->executeQuery()
             ->fetchOne() !== '';
     }
+
+    /**
+     * @param string $fieldName
+     * @param string $tableName
+     * @return bool
+     * @throws ExceptionDbal
+     */
+    public static function isAnyFieldFilledInTable(string $fieldName, string $tableName): bool
+    {
+        $queryBuilder = self::getQueryBuilderForTable($tableName);
+        return $queryBuilder
+            ->select($fieldName)
+            ->from($tableName)
+            ->where($fieldName . ' != \'\'')
+            ->setMaxResults(1)
+            ->executeQuery()
+            ->fetchOne() !== false;
+    }
 }
diff --git a/Configuration/TCA/tx_lux_domain_model_download.php b/Configuration/TCA/tx_lux_domain_model_download.php
index 538219e0..6e5dfcdb 100644
--- a/Configuration/TCA/tx_lux_domain_model_download.php
+++ b/Configuration/TCA/tx_lux_domain_model_download.php
@@ -22,7 +22,7 @@
         'hideTable' => true,
     ],
     'types' => [
-        '1' => ['showitem' => 'crdate,href,page,file,properties,domain,visitor'],
+        '1' => ['showitem' => 'crdate,href,page,file,properties,domain,site,visitor'],
     ],
     'columns' => [
         'sys_language_uid' => [
@@ -104,6 +104,15 @@
                 'readOnly' => true,
             ],
         ],
+        'site' => [
+            'exclude' => true,
+            'label' => 'LLL:EXT:lux/Resources/Private/Language/locallang_db.xlf:' . Download::TABLE_NAME . '.site',
+            'config' => [
+                'type' => 'input',
+                'size' => 30,
+                'readOnly' => true,
+            ],
+        ],
         'visitor' => [
             'exclude' => true,
             'label' => 'LLL:EXT:lux/Resources/Private/Language/locallang_db.xlf:' . Download::TABLE_NAME . '.visitor',
diff --git a/Configuration/TCA/tx_lux_domain_model_linkclick.php b/Configuration/TCA/tx_lux_domain_model_linkclick.php
index e6d9b627..442ab489 100644
--- a/Configuration/TCA/tx_lux_domain_model_linkclick.php
+++ b/Configuration/TCA/tx_lux_domain_model_linkclick.php
@@ -21,7 +21,7 @@
         'hideTable' => true,
     ],
     'types' => [
-        '1' => ['showitem' => 'crdate,linklistener,page,visitor'],
+        '1' => ['showitem' => 'crdate,linklistener,page,site,visitor'],
     ],
     'columns' => [
         'sys_language_uid' => [
@@ -86,6 +86,15 @@
                 'readOnly' => true,
             ],
         ],
+        'site' => [
+            'exclude' => true,
+            'label' => 'LLL:EXT:lux/Resources/Private/Language/locallang_db.xlf:' . Linkclick::TABLE_NAME . '.site',
+            'config' => [
+                'type' => 'input',
+                'size' => 30,
+                'readOnly' => true,
+            ],
+        ],
         'visitor' => [
             'exclude' => true,
             'label' => 'LLL:EXT:lux/Resources/Private/Language/locallang_db.xlf:' . Linkclick::TABLE_NAME . '.visitor',
diff --git a/Configuration/TCA/tx_lux_domain_model_pagevisit.php b/Configuration/TCA/tx_lux_domain_model_pagevisit.php
index 1f6ad376..84007a45 100644
--- a/Configuration/TCA/tx_lux_domain_model_pagevisit.php
+++ b/Configuration/TCA/tx_lux_domain_model_pagevisit.php
@@ -25,7 +25,7 @@
         'hideTable' => true,
     ],
     'types' => [
-        '1' => ['showitem' => 'page,language,crdate,referrer,domain,visitor'],
+        '1' => ['showitem' => 'page,language,crdate,referrer,domain,site,visitor'],
     ],
     'columns' => [
         'sys_language_uid' => [
@@ -134,6 +134,15 @@
                 'readOnly' => true,
             ],
         ],
+        'site' => [
+            'exclude' => true,
+            'label' => 'LLL:EXT:lux/Resources/Private/Language/locallang_db.xlf:' . Pagevisit::TABLE_NAME . '.site',
+            'config' => [
+                'type' => 'input',
+                'size' => 30,
+                'readOnly' => true,
+            ],
+        ],
         'visitor' => [
             'exclude' => true,
             'label' => 'LLL:EXT:lux/Resources/Private/Language/locallang_db.xlf:' . Pagevisit::TABLE_NAME . '.visitor',
diff --git a/Resources/Private/Language/de.locallang_db.xlf b/Resources/Private/Language/de.locallang_db.xlf
index 5350e4c8..3a8ffae1 100644
--- a/Resources/Private/Language/de.locallang_db.xlf
+++ b/Resources/Private/Language/de.locallang_db.xlf
@@ -165,6 +165,10 @@
 				<source>Current domain</source>
 				<target state="translated">Aktuelle Domain</target>
 			</trans-unit>
+			<trans-unit id="tx_lux_domain_model_pagevisit.site">
+				<source>Site</source>
+				<target state="translated">Site</target>
+			</trans-unit>
 			<trans-unit id="tx_lux_domain_model_pagevisit.visitor">
 				<source>Lead</source>
 				<target state="translated">Lead</target>
@@ -244,6 +248,14 @@
 				<source>File</source>
 				<target state="translated">Datei</target>
 			</trans-unit>
+			<trans-unit id="tx_lux_domain_model_download.domain">
+				<source>Domain</source>
+				<target state="translated">Domain</target>
+			</trans-unit>
+			<trans-unit id="tx_lux_domain_model_download.site">
+				<source>Site</source>
+				<target state="translated">Site</target>
+			</trans-unit>
 			<trans-unit id="tx_lux_domain_model_download.visitor">
 				<source>Lead</source>
 				<target state="translated">Lead</target>
@@ -452,6 +464,10 @@
 				<source>Page</source>
 				<target state="translated">Seite</target>
 			</trans-unit>
+			<trans-unit id="tx_lux_domain_model_linkclick.site">
+				<source>Site</source>
+				<target state="translated">Site</target>
+			</trans-unit>
 			<trans-unit id="tx_lux_domain_model_linkclick.visitor">
 				<source>Lead</source>
 				<target state="translated">Lead</target>
diff --git a/Resources/Private/Language/locallang_db.xlf b/Resources/Private/Language/locallang_db.xlf
index ff305d1c..3ca3639b 100644
--- a/Resources/Private/Language/locallang_db.xlf
+++ b/Resources/Private/Language/locallang_db.xlf
@@ -125,6 +125,8 @@
 			<trans-unit id="tx_lux_domain_model_pagevisit.domain">
 				<source>Current domain</source>
 			</trans-unit>
+			<trans-unit id="tx_lux_domain_model_pagevisit.site">
+				<source>Site</source>
 			<trans-unit id="tx_lux_domain_model_pagevisit.visitor">
 				<source>Lead</source>
 			</trans-unit>
@@ -185,6 +187,12 @@
 			<trans-unit id="tx_lux_domain_model_download.file">
 				<source>File</source>
 			</trans-unit>
+			<trans-unit id="tx_lux_domain_model_download.domain">
+				<source>Domain</source>
+			</trans-unit>
+			<trans-unit id="tx_lux_domain_model_download.site">
+				<source>Site</source>
+			</trans-unit>
 			<trans-unit id="tx_lux_domain_model_download.visitor">
 				<source>Lead</source>
 			</trans-unit>
@@ -344,6 +352,9 @@
 			<trans-unit id="tx_lux_domain_model_linkclick.page">
 				<source>Page</source>
 			</trans-unit>
+			<trans-unit id="tx_lux_domain_model_linkclick.site">
+				<source>Site</source>
+			</trans-unit>
 			<trans-unit id="tx_lux_domain_model_linkclick.visitor">
 				<source>Lead</source>
 			</trans-unit>
diff --git a/ext_localconf.php b/ext_localconf.php
index 92ae4433..cc4a644a 100644
--- a/ext_localconf.php
+++ b/ext_localconf.php
@@ -83,5 +83,14 @@ function () {
          * CacheHash: Add LUX paramters to excluded variables
          */
         \In2code\Lux\Utility\CacheHashUtility::addLuxArgumentsToExcludedVariables();
+
+        /**
+         * Upgrade Wizards
+         * Todo: Can be removed when TYPO3 11 support is dropped
+         */
+        if (\In2code\Lux\Utility\ConfigurationUtility::isTypo3Version11()) {
+            $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['ext/install']['update']['addSitesUpgradeWizard']
+                = \In2code\Lux\Update\AddSitesUpgradeWizard::class;
+        }
     }
 );
diff --git a/ext_tables.sql b/ext_tables.sql
index 7c017c6b..ce0991c9 100644
--- a/ext_tables.sql
+++ b/ext_tables.sql
@@ -126,6 +126,7 @@ CREATE TABLE tx_lux_domain_model_pagevisit (
 	language int(11) DEFAULT '0' NOT NULL,
 	referrer text DEFAULT '' NOT NULL,
 	domain varchar(255) DEFAULT '' NOT NULL,
+	site varchar(255) DEFAULT '' NOT NULL,
 
 	tstamp int(11) unsigned DEFAULT '0' NOT NULL,
 	crdate int(11) unsigned DEFAULT '0' NOT NULL,
@@ -143,6 +144,7 @@ CREATE TABLE tx_lux_domain_model_pagevisit (
 	KEY parent (pid),
 	KEY visitor (visitor),
 	KEY page (page),
+	KEY site (site(50)),
 	KEY language_lux (language),
 	KEY referrer (referrer(50)),
 	KEY domain (domain(50)),
@@ -194,6 +196,7 @@ CREATE TABLE tx_lux_domain_model_download (
 	href varchar(255) DEFAULT '' NOT NULL,
 	page int(11) DEFAULT '0' NOT NULL,
 	domain varchar(255) DEFAULT '' NOT NULL,
+	site varchar(255) DEFAULT '' NOT NULL,
 
 	tstamp int(11) unsigned DEFAULT '0' NOT NULL,
 	crdate int(11) unsigned DEFAULT '0' NOT NULL,
@@ -211,6 +214,7 @@ CREATE TABLE tx_lux_domain_model_download (
 	KEY href (href(50)),
 	KEY page (page),
 	KEY domain (domain(50)),
+	KEY site (site(50)),
 	KEY crdate (crdate),
 	KEY language (l10n_parent,sys_language_uid)
 );
@@ -252,6 +256,7 @@ CREATE TABLE tx_lux_domain_model_search (
 	visitor int(11) unsigned DEFAULT '0' NOT NULL,
 
 	searchterm varchar(255) DEFAULT '' NOT NULL,
+	pagevisit int(11) DEFAULT '0' NOT NULL,
 
 	tstamp int(11) unsigned DEFAULT '0' NOT NULL,
 	crdate int(11) unsigned DEFAULT '0' NOT NULL,
@@ -266,6 +271,7 @@ CREATE TABLE tx_lux_domain_model_search (
 	KEY parent (pid),
 	KEY visitor (visitor),
 	KEY searchterm (searchterm(20)),
+	KEY pagevisit (pagevisit),
 	KEY crdate (crdate),
 	KEY language (l10n_parent,sys_language_uid)
 );
@@ -332,6 +338,7 @@ CREATE TABLE tx_lux_domain_model_linkclick (
 
 	page int(11) DEFAULT '0' NOT NULL,
 	linklistener int(11) DEFAULT '0' NOT NULL,
+	site varchar(255) DEFAULT '' NOT NULL,
 
 	tstamp int(11) unsigned DEFAULT '0' NOT NULL,
 	crdate int(11) unsigned DEFAULT '0' NOT NULL,
@@ -347,6 +354,7 @@ CREATE TABLE tx_lux_domain_model_linkclick (
 	KEY visitor (visitor),
 	KEY page (page),
 	KEY linklistener (linklistener),
+	KEY site (site(50)),
 	KEY crdate (crdate),
 	KEY language (l10n_parent,sys_language_uid)
 );