diff --git a/src/bundle/Core/Command/CopySubtreeCommand.php b/src/bundle/Core/Command/CopySubtreeCommand.php
index 3c1f01c5a6..9febb83ae8 100644
--- a/src/bundle/Core/Command/CopySubtreeCommand.php
+++ b/src/bundle/Core/Command/CopySubtreeCommand.php
@@ -127,7 +127,7 @@ protected function execute(InputInterface $input, OutputInterface $output): int
             $targetLocation->getContentInfo()->contentTypeId
         );
 
-        if (!$targetContentType->isContainer) {
+        if (!$targetContentType->isContainer()) {
             throw new InvalidArgumentException(
                 'target-location-id',
                 'The selected Location cannot contain children'
diff --git a/src/contracts/Repository/Values/ContentType/ContentType.php b/src/contracts/Repository/Values/ContentType/ContentType.php
index 997de48c56..964ae784f0 100644
--- a/src/contracts/Repository/Values/ContentType/ContentType.php
+++ b/src/contracts/Repository/Values/ContentType/ContentType.php
@@ -27,7 +27,6 @@
  * @property-read string $remoteId a global unique id of the content object
  * @property-read string $urlAliasSchema URL alias schema. If nothing is provided, $nameSchema will be used instead.
  * @property-read string $nameSchema  The name schema.
- * @property-read bool $isContainer @deprecated use strict getter {@see ContentType::isContainer} instead.
  * @property-read string $mainLanguageCode the main language of the content type names and description used for fallback.
  * @property-read bool $defaultAlwaysAvailable if an instance of a content type is created the always available flag is set by default this this value.
  * @property-read string[] $languageCodes array of language codes used by content type translations.
diff --git a/src/contracts/Specification/Content/ContentContainerSpecification.php b/src/contracts/Specification/Content/ContentContainerSpecification.php
index 59cb4c03e5..8f7b1cc5b4 100644
--- a/src/contracts/Specification/Content/ContentContainerSpecification.php
+++ b/src/contracts/Specification/Content/ContentContainerSpecification.php
@@ -14,6 +14,6 @@ final class ContentContainerSpecification implements ContentSpecification
 {
     public function isSatisfiedBy(Content $content): bool
     {
-        return $content->getContentType()->isContainer;
+        return $content->getContentType()->isContainer();
     }
 }
diff --git a/src/lib/Repository/LocationService.php b/src/lib/Repository/LocationService.php
index bf6dc27979..b37a0ac5ed 100644
--- a/src/lib/Repository/LocationService.php
+++ b/src/lib/Repository/LocationService.php
@@ -688,7 +688,7 @@ public function moveSubtree(APILocation $location, APILocation $newParentLocatio
             );
         }
         $contentTypeId = $newParentLocation->contentInfo->contentTypeId;
-        if (!$this->contentTypeService->loadContentType($contentTypeId)->isContainer) {
+        if (!$this->contentTypeService->loadContentType($contentTypeId)->isContainer()) {
             throw new InvalidArgumentException(
                 '$newParentLocation',
                 'Cannot move Location to a parent that is not a container'
diff --git a/src/lib/Repository/Mapper/ContentTypeDomainMapper.php b/src/lib/Repository/Mapper/ContentTypeDomainMapper.php
index c352b17e99..05dab96cc3 100644
--- a/src/lib/Repository/Mapper/ContentTypeDomainMapper.php
+++ b/src/lib/Repository/Mapper/ContentTypeDomainMapper.php
@@ -155,7 +155,7 @@ public function buildSPIContentTypeUpdateStruct(APIContentTypeDraft $contentType
 
         $updateStruct->isContainer = $contentTypeUpdateStruct->isContainer !== null ?
             $contentTypeUpdateStruct->isContainer :
-            $contentTypeDraft->isContainer;
+            $contentTypeDraft->isContainer();
         $updateStruct->sortField = $contentTypeUpdateStruct->defaultSortField !== null ?
             $contentTypeUpdateStruct->defaultSortField :
             $contentTypeDraft->defaultSortField;
@@ -183,6 +183,7 @@ public function buildContentTypeDraftDomainObject(SPIContentType $spiContentType
         return new ContentTypeDraft(
             [
                 'innerContentType' => $this->buildContentTypeDomainObject($spiContentType),
+                'isContainer' => false,
             ]
         );
     }