diff --git a/ChangeLog-10.1.md b/ChangeLog-10.1.md
index b7299e7b4..603efad46 100644
--- a/ChangeLog-10.1.md
+++ b/ChangeLog-10.1.md
@@ -2,6 +2,12 @@
 
 All notable changes are documented in this file using the [Keep a CHANGELOG](http://keepachangelog.com/) principles.
 
+## [10.1.12] - 2024-03-02
+
+### Changed
+
+* Do not use implicitly nullable parameters
+
 ## [10.1.11] - 2023-12-21
 
 ### Changed
@@ -83,6 +89,7 @@ All notable changes are documented in this file using the [Keep a CHANGELOG](htt
 
 * The `SebastianBergmann\CodeCoverage\Filter::includeDirectory()`, `SebastianBergmann\CodeCoverage\Filter::excludeDirectory()`, and `SebastianBergmann\CodeCoverage\Filter::excludeFile()` methods are now deprecated
 
+[10.1.12]: https://github.com/sebastianbergmann/php-code-coverage/compare/10.1.11...10.1.12
 [10.1.11]: https://github.com/sebastianbergmann/php-code-coverage/compare/10.1.10...10.1.11
 [10.1.10]: https://github.com/sebastianbergmann/php-code-coverage/compare/10.1.9...10.1.10
 [10.1.9]: https://github.com/sebastianbergmann/php-code-coverage/compare/10.1.8...10.1.9
diff --git a/src/CodeCoverage.php b/src/CodeCoverage.php
index 0fe09e277..805fd8223 100644
--- a/src/CodeCoverage.php
+++ b/src/CodeCoverage.php
@@ -160,7 +160,7 @@ public function setTests(array $tests): void
         $this->tests = $tests;
     }
 
-    public function start(string $id, TestSize $size = null, bool $clear = false): void
+    public function start(string $id, ?TestSize $size = null, bool $clear = false): void
     {
         if ($clear) {
             $this->clear();
@@ -177,7 +177,7 @@ public function start(string $id, TestSize $size = null, bool $clear = false): v
     /**
      * @psalm-param array<string,list<int>> $linesToBeIgnored
      */
-    public function stop(bool $append = true, TestStatus $status = null, array|false $linesToBeCovered = [], array $linesToBeUsed = [], array $linesToBeIgnored = []): RawCodeCoverageData
+    public function stop(bool $append = true, ?TestStatus $status = null, array|false $linesToBeCovered = [], array $linesToBeUsed = [], array $linesToBeIgnored = []): RawCodeCoverageData
     {
         $data = $this->driver->stop();
 
@@ -202,7 +202,7 @@ public function stop(bool $append = true, TestStatus $status = null, array|false
      * @throws TestIdMissingException
      * @throws UnintentionallyCoveredCodeException
      */
-    public function append(RawCodeCoverageData $rawData, string $id = null, bool $append = true, TestStatus $status = null, array|false $linesToBeCovered = [], array $linesToBeUsed = [], array $linesToBeIgnored = []): void
+    public function append(RawCodeCoverageData $rawData, ?string $id = null, bool $append = true, ?TestStatus $status = null, array|false $linesToBeCovered = [], array $linesToBeUsed = [], array $linesToBeIgnored = []): void
     {
         if ($id === null) {
             $id = $this->currentId;
diff --git a/src/Node/AbstractNode.php b/src/Node/AbstractNode.php
index 6338ed3d0..3f21a50e7 100644
--- a/src/Node/AbstractNode.php
+++ b/src/Node/AbstractNode.php
@@ -33,7 +33,7 @@ abstract class AbstractNode implements Countable
     private readonly ?AbstractNode $parent;
     private string $id;
 
-    public function __construct(string $name, self $parent = null)
+    public function __construct(string $name, ?self $parent = null)
     {
         if (str_ends_with($name, DIRECTORY_SEPARATOR)) {
             $name = substr($name, 0, -1);
diff --git a/src/Version.php b/src/Version.php
index c7739dc6e..41f657710 100644
--- a/src/Version.php
+++ b/src/Version.php
@@ -19,7 +19,7 @@ final class Version
     public static function id(): string
     {
         if (self::$version === '') {
-            self::$version = (new VersionId('10.1.11', dirname(__DIR__)))->asString();
+            self::$version = (new VersionId('10.1.12', dirname(__DIR__)))->asString();
         }
 
         return self::$version;