diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 1e85da9..c1ec233 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -112,6 +112,12 @@ jobs:
             typo3-version: '^12.4'
           - php-version: '8.3'
             typo3-version: '^12.4'
+          - php-version: '8.1'
+            typo3-version: '^13.4'
+          - php-version: '8.2'
+            typo3-version: '^13.4'
+          - php-version: '8.3'
+            typo3-version: '^13.4'
     steps:
       - uses: actions/checkout@v3
 
diff --git a/Classes/Service/VariablesService.php b/Classes/Service/VariablesService.php
index e7cb415..4db444e 100644
--- a/Classes/Service/VariablesService.php
+++ b/Classes/Service/VariablesService.php
@@ -215,7 +215,7 @@ public function getNearestTimestampForMarkers(array $usedMarkerKeys): int
                     . 'CASE WHEN '
                     . $queryBuilder->expr()->lte(
                         $timeFields[$field],
-                        $queryBuilder->createNamedParameter($now, \PDO::PARAM_INT)
+                        $queryBuilder->createNamedParameter($now, Connection::PARAM_INT)
                     )
                     . ' THEN NULL ELSE ' . $queryBuilder->quoteIdentifier($timeFields[$field]) . ' END'
                     . ') AS ' . $queryBuilder->quoteIdentifier($timeFields[$field])
@@ -223,7 +223,7 @@ public function getNearestTimestampForMarkers(array $usedMarkerKeys): int
                 $timeConditions->with(
                     $queryBuilder->expr()->gt(
                         $timeFields[$field],
-                        $queryBuilder->createNamedParameter($now, \PDO::PARAM_INT)
+                        $queryBuilder->createNamedParameter($now, Connection::PARAM_INT)
                     )
                 );
             }
@@ -239,8 +239,8 @@ public function getNearestTimestampForMarkers(array $usedMarkerKeys): int
                     $timeConditions
                 );
             $row = $queryBuilder
-                ->execute()
-                ->fetch();
+                ->executeQuery()
+                ->fetchAssociative();
 
             if ($row) {
                 foreach (array_keys($timeFields) as $timeField) {
diff --git a/composer.json b/composer.json
index 7caa296..aa9a3f4 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,7 @@
   "require": {
     "php": ">= 8.1 < 8.4",
     "ramsey/collection": "^2.0",
-    "typo3/cms-core": "^12.4"
+    "typo3/cms-core": "^12.4 || ^13.4"
   },
   "require-dev": {
     "rector/rector": "^0.12.23",