diff --git a/Classes/Wwwision/Neos/MailChimp/Domain/Dto/CallbackQuery.php b/Classes/Wwwision/Neos/MailChimp/Domain/Dto/CallbackQuery.php
index 81f0ff6..06e948a 100644
--- a/Classes/Wwwision/Neos/MailChimp/Domain/Dto/CallbackQuery.php
+++ b/Classes/Wwwision/Neos/MailChimp/Domain/Dto/CallbackQuery.php
@@ -52,9 +52,9 @@ public function __construct(\Closure $resultCallback, \Closure $countCallback =
      *
      * @return string
      */
-    public function getType()
+    public function getType(): string
     {
-        return null;
+        return '';
     }
 
     /**
@@ -63,7 +63,7 @@ public function getType()
      * @param boolean $cacheResult If the result cache should be used
      * @return QueryResultInterface The query result
      */
-    public function execute($cacheResult = false)
+    public function execute($cacheResult = false): QueryResultInterface
     {
         return new CallbackQueryResult($this);
     }
@@ -81,7 +81,7 @@ public function getResult(): array
      *
      * @return integer The query result count
      */
-    public function count()
+    public function count(): int
     {
         if ($this->countCallback !== null) {
             return call_user_func_array($this->countCallback, [$this]);
@@ -99,7 +99,7 @@ public function count()
      * @param array $orderings The property names to order by
      * @return QueryInterface
      */
-    public function setOrderings(array $orderings)
+    public function setOrderings(array $orderings): QueryInterface
     {
         $this->orderings = $orderings;
         return $this;
@@ -114,7 +114,7 @@ public function setOrderings(array $orderings)
      *
      * @return array
      */
-    public function getOrderings()
+    public function getOrderings(): array
     {
         return $this->orderings;
     }
@@ -126,7 +126,7 @@ public function getOrderings()
      * @param integer $limit
      * @return QueryInterface
      */
-    public function setLimit($limit)
+    public function setLimit($limit): QueryInterface
     {
         $this->limit = $limit;
         return $this;
@@ -137,7 +137,7 @@ public function setLimit($limit)
      *
      * @return integer
      */
-    public function getLimit()
+    public function getLimit(): ?int
     {
         return $this->limit;
     }
@@ -149,7 +149,7 @@ public function getLimit()
      * @param integer $offset
      * @return QueryInterface
      */
-    public function setOffset($offset)
+    public function setOffset($offset): QueryInterface
     {
         $this->offset = $offset;
         return $this;
@@ -160,7 +160,7 @@ public function setOffset($offset)
      *
      * @return integer
      */
-    public function getOffset()
+    public function getOffset(): ?int
     {
         return $this->offset;
     }
@@ -168,7 +168,7 @@ public function getOffset()
     /**
      * @param object $constraint Some constraint, depending on the backend
      */
-    public function matching($constraint)
+    public function matching($constraint): QueryInterface
     {
         throw new \BadMethodCallException('This method is not implemented in this query implementation.');
     }
@@ -290,14 +290,14 @@ public function greaterThanOrEqual($propertyName, $operand)
     /**
      * @param boolean $distinct
      */
-    public function setDistinct($distinct = true)
+    public function setDistinct($distinct = true): QueryInterface
     {
         throw new \BadMethodCallException('This method is not implemented in this query implementation.');
     }
 
     /**
      */
-    public function isDistinct()
+    public function isDistinct(): bool
     {
         throw new \BadMethodCallException('This method is not implemented in this query implementation.');
     }
diff --git a/Classes/Wwwision/Neos/MailChimp/Domain/Dto/CallbackQueryResult.php b/Classes/Wwwision/Neos/MailChimp/Domain/Dto/CallbackQueryResult.php
index e4656a1..5ef6ad4 100644
--- a/Classes/Wwwision/Neos/MailChimp/Domain/Dto/CallbackQueryResult.php
+++ b/Classes/Wwwision/Neos/MailChimp/Domain/Dto/CallbackQueryResult.php
@@ -3,6 +3,7 @@
 
 namespace Wwwision\Neos\MailChimp\Domain\Dto;
 
+use Neos\Flow\Persistence\QueryInterface;
 use Neos\Flow\Persistence\QueryResultInterface;
 
 /**
@@ -45,7 +46,7 @@ protected function initialize(): void
      *
      * @return CallbackQuery
      */
-    public function getQuery()
+    public function getQuery(): QueryInterface
     {
         return clone $this->query;
     }
@@ -83,7 +84,7 @@ public function count()
      *
      * @return array
      */
-    public function toArray()
+    public function toArray(): array
     {
         $this->initialize();
         return $this->results;
diff --git a/composer.json b/composer.json
index d0c5970..1378308 100644
--- a/composer.json
+++ b/composer.json
@@ -4,7 +4,7 @@
     "description": "Flow package that integrates MailChimp into your Neos site / Flow Application",
     "license": "GPL-3.0+",
     "require": {
-        "neos/neos": "^5.0"
+        "neos/neos": "^5.0 || ^7.0"
     },
     "autoload": {
         "psr-0": {
@@ -85,7 +85,15 @@
             "Neos.Fusion-20180211184832",
             "Neos.Flow-20180415105700",
             "Neos.Neos-20180907103800",
-            "Neos.Neos.Ui-20190319094900"
+            "Neos.Neos.Ui-20190319094900",
+            "Neos.ContentRepository.Search-20161210231100",
+            "Neos.Flow-20190425144900",
+            "Neos.Flow-20190515215000",
+            "Neos.Flow-20200813181400",
+            "Neos.Flow-20201003165200",
+            "Neos.Flow-20201109224100",
+            "Neos.Flow-20201205172733",
+            "Neos.Flow-20201207104500"
         ]
     }
-}
\ No newline at end of file
+}