diff --git a/composer.json b/composer.json
index f263f2f..86d1ef9 100644
--- a/composer.json
+++ b/composer.json
@@ -12,7 +12,7 @@
 	"require": {
 		"php":            ">=7.1.0",
 		"ext-json": "*",
-		"league/fractal": "^0.19.2",
+		"league/fractal": "^0.20.0",
 		"yiisoft/yii2":   "~2.0.15"
 		
 	},
diff --git a/src/JsonApiError.php b/src/JsonApiError.php
index b8e8d75..b3022bc 100644
--- a/src/JsonApiError.php
+++ b/src/JsonApiError.php
@@ -21,6 +21,7 @@ class JsonApiError extends BaseObject implements JsonSerializable
     public $source;
     public $meta = [];
 
+    #[\ReturnTypeWillChange]
     public function jsonSerialize()
     {
         $base = [
diff --git a/src/pagination/JsonApiPaginator.php b/src/pagination/JsonApiPaginator.php
index 93111df..85b9a39 100644
--- a/src/pagination/JsonApiPaginator.php
+++ b/src/pagination/JsonApiPaginator.php
@@ -53,12 +53,12 @@ class JsonApiPaginator extends Pagination implements PaginatorInterface
     /**
      * @var boolean
      * Indicate, should paginator provide absolute urls or relative
-    */
+     */
     public $absoluteUrls = true;
 
     /**
      * @var int calculated current page number
-    */
+     */
     private $_page;
 
     public function init()
@@ -68,32 +68,32 @@ public function init()
         $this->pageParam = 'number';
     }
 
-    public function getCurrentPage()
+    public function getCurrentPage(): int
     {
         return $this->getPage();
     }
 
-    public function getLastPage()
+    public function getLastPage(): int
     {
         return $this->getPageCount();
     }
 
-    public function getTotal()
+    public function getTotal(): int
     {
         return $this->totalCount;
     }
 
-    public function getCount()
+    public function getCount(): int
     {
         return $this->itemsCount;
     }
 
-    public function getPerPage()
+    public function getPerPage(): int
     {
         return $this->getPageSize();
     }
 
-    public function getUrl($page)
+    public function getUrl($page): string
     {
         return $this->createUrl($page);
     }