diff --git a/Content/StructureResolver.php b/Content/StructureResolver.php
index 04cc8f3..4f8cfce 100644
--- a/Content/StructureResolver.php
+++ b/Content/StructureResolver.php
@@ -126,7 +126,7 @@ public function resolveProperties(
             }
 
             // the '.' is used to separate the extension name from the property name.
-            if (\str_contains($sourceProperty, '.')) {
+            if (false !== \strpos($sourceProperty, '.')) {
                 [$extensionName, $propertyName] = \explode('.', $sourceProperty);
 
                 if (!isset($unresolvedExtensionData[$extensionName][$propertyName])) {