diff --git a/ChangeLog.md b/ChangeLog.md
index 39f3a54..f261d31 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -2,6 +2,12 @@
 
 All notable changes are documented in this file using the [Keep a CHANGELOG](https://keepachangelog.com/) principles.
 
+## [5.1.2] - 2024-03-02
+
+### Changed
+
+* Do not use implicitly nullable parameters
+
 ## [5.1.1] - 2023-09-24
 
 ### Changed
@@ -94,6 +100,7 @@ All notable changes are documented in this file using the [Keep a CHANGELOG](htt
 
 * Remove HHVM-specific code that is no longer needed
 
+[5.1.2]: https://github.com/sebastianbergmann/exporter/compare/5.1.1...5.1.2
 [5.1.1]: https://github.com/sebastianbergmann/exporter/compare/5.1.0...5.1.1
 [5.1.0]: https://github.com/sebastianbergmann/exporter/compare/5.0.1...5.1.0
 [5.0.1]: https://github.com/sebastianbergmann/exporter/compare/5.0.0...5.0.1
diff --git a/src/Exporter.php b/src/Exporter.php
index 6bc19e0..0577075 100644
--- a/src/Exporter.php
+++ b/src/Exporter.php
@@ -54,7 +54,7 @@ final class Exporter
         return $this->recursiveExport($value, $indentation);
     }
 
-    public function shortenedRecursiveExport(array &$data, Context $context = null): string
+    public function shortenedRecursiveExport(array &$data, ?Context $context = null): string
     {
         $result   = [];
         $exporter = new self;