diff -u -r Slim/Collection.php Slim/Collection.php
--- Slim/Collection.php	2019-11-28 09:40:33.000000000 -0800
+++ Slim/Collection.php	2022-10-18 21:25:54.603075152 -0700
@@ -109,6 +109,7 @@
      *
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function offsetExists($key)
     {
         return $this->has($key);
@@ -121,6 +122,7 @@
      *
      * @return mixed The key's value, or the default value
      */
+    #[\ReturnTypeWillChange]
     public function offsetGet($key)
     {
         return $this->get($key);
@@ -132,6 +134,7 @@
      * @param string $key   The data key
      * @param mixed  $value The data value
      */
+    #[\ReturnTypeWillChange]
     public function offsetSet($key, $value)
     {
         $this->set($key, $value);
@@ -142,6 +145,7 @@
      *
      * @param string $key The data key
      */
+    #[\ReturnTypeWillChange]
     public function offsetUnset($key)
     {
         $this->remove($key);
@@ -152,6 +156,7 @@
      *
      * @return int
      */
+    #[\ReturnTypeWillChange]
     public function count()
     {
         return count($this->data);
@@ -162,6 +167,7 @@
      *
      * @return ArrayIterator
      */
+    #[\ReturnTypeWillChange]
     public function getIterator()
     {
         return new ArrayIterator($this->data);
diff -u -r Slim/Http/Uri.php Slim/Http/Uri.php
--- Slim/Http/Uri.php	2019-11-28 09:40:33.000000000 -0800
+++ Slim/Http/Uri.php	2022-10-19 07:45:34.196533740 -0700
@@ -718,7 +718,7 @@
             function ($match) {
                 return rawurlencode($match[0]);
             },
-            $query
+            $query ?? ''
         );
     }
 
diff -u -r Slim/Http/Request.php Slim/Http/Request.php
--- Slim/Http/Request.php	2019-11-28 09:40:33.000000000 -0800
+++ Slim/Http/Request.php	2022-10-19 12:56:21.077660825 -0700
@@ -1016,7 +1016,7 @@
         // Check if this specific media type has a parser registered first
         if (!isset($this->bodyParsers[$mediaType])) {
             // If not, look for a media type with a structured syntax suffix (RFC 6839)
-            $parts = explode('+', $mediaType);
+            $parts = explode('+', $mediaType ?? '');
             if (count($parts) >= 2) {
                 $mediaType = 'application/' . $parts[count($parts)-1];
             }