diff --git a/.github/actions/setup/action.yml b/.github/actions/setup/action.yml
index da58ba8a5..48d916394 100644
--- a/.github/actions/setup/action.yml
+++ b/.github/actions/setup/action.yml
@@ -49,7 +49,5 @@ runs:
     - name: Install dependencies with Composer
       uses: ramsey/composer-install@3.0.0
       with:
-        # Revert when psalm supports PHP 8.4
-        # composer-options: "--no-suggest"
-        composer-options: "--no-suggest ${{ inputs.php-version == '8.4' && '--ignore-platform-req=php+' || '' }}"
+        composer-options: "--no-suggest"
         working-directory: "${{ inputs.working-directory }}"
diff --git a/composer.json b/composer.json
index 5a2c10def..f4aee2618 100644
--- a/composer.json
+++ b/composer.json
@@ -24,7 +24,7 @@
         "phpunit/phpunit": "^10.5.35",
         "rector/rector": "^1.2",
         "squizlabs/php_codesniffer": "^3.7",
-        "vimeo/psalm": "^5.13"
+        "vimeo/psalm": "^6.5"
     },
     "replace": {
         "mongodb/builder": "*"
diff --git a/psalm-baseline.xml b/psalm-baseline.xml
index 321bbc05a..eb68663a1 100644
--- a/psalm-baseline.xml
+++ b/psalm-baseline.xml
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<files psalm-version="5.26.1@d747f6500b38ac4f7dfc5edbcae6e4b637d7add0">
+<files psalm-version="6.5.1@3f17a6b24a2dbe543e21408c2b19108cf6a355ef">
   <file src="examples/atlas_search.php">
     <MixedArgument>
       <code><![CDATA[$document['name']]]></code>
@@ -398,11 +398,6 @@
       <code><![CDATA[$this->current()]]></code>
     </PossiblyNullArgument>
   </file>
-  <file src="src/Model/CodecCursor.php">
-    <TooManyArguments>
-      <code><![CDATA[getId]]></code>
-    </TooManyArguments>
-  </file>
   <file src="src/Model/CollectionInfoCommandIterator.php">
     <DeprecatedInterface>
       <code><![CDATA[CollectionInfoCommandIterator]]></code>
@@ -754,9 +749,6 @@
       <code><![CDATA[$options['writeConcern']]]></code>
       <code><![CDATA[$value]]></code>
     </MixedAssignment>
-    <MixedInferredReturnType>
-      <code><![CDATA[array|object|null]]></code>
-    </MixedInferredReturnType>
     <MixedMethodCall>
       <code><![CDATA[decode]]></code>
       <code><![CDATA[isInTransaction]]></code>
@@ -772,9 +764,6 @@
     <MixedAssignment>
       <code><![CDATA[$document]]></code>
     </MixedAssignment>
-    <MixedInferredReturnType>
-      <code><![CDATA[array|object|null]]></code>
-    </MixedInferredReturnType>
     <MixedReturnStatement>
       <code><![CDATA[$document === false ? null : $document]]></code>
       <code><![CDATA[$document === false ? null : $document]]></code>
@@ -922,9 +911,6 @@
     <MixedAssignment>
       <code><![CDATA[$this->postBatchResumeToken]]></code>
     </MixedAssignment>
-    <MixedInferredReturnType>
-      <code><![CDATA[array|object|null]]></code>
-    </MixedInferredReturnType>
     <MixedPropertyFetch>
       <code><![CDATA[$reply->cursor->firstBatch]]></code>
       <code><![CDATA[$reply->cursor->postBatchResumeToken]]></code>
@@ -963,10 +949,6 @@
       <code><![CDATA[$typeMap['fieldPaths'][$fieldPath]]]></code>
       <code><![CDATA[$value]]></code>
     </MixedAssignment>
-    <MixedInferredReturnType>
-      <code><![CDATA[array|object|null]]></code>
-      <code><![CDATA[array|object|null]]></code>
-    </MixedInferredReturnType>
     <MixedReturnStatement>
       <code><![CDATA[$collectionInfo['options']['encryptedFields'] ?? null]]></code>
       <code><![CDATA[$collectionInfo['options']['encryptedFields'] ?? null]]></code>
diff --git a/psalm.xml.dist b/psalm.xml.dist
index 83d825d51..ba737bd6a 100644
--- a/psalm.xml.dist
+++ b/psalm.xml.dist
@@ -2,6 +2,8 @@
 <psalm
     errorLevel="1"
     errorBaseline="psalm-baseline.xml"
+    ignoreInternalFunctionFalseReturn="true"
+    ignoreInternalFunctionNullReturn="true"
     resolveFromConfigFile="true"
     findUnusedBaselineEntry="true"
     findUnusedCode="false"
@@ -17,12 +19,6 @@
         </ignoreFiles>
     </projectFiles>
 
-    <stubs>
-        <file name="stubs/BSON/Document.stub.php"/>
-        <file name="stubs/BSON/Iterator.stub.php"/>
-        <file name="stubs/BSON/PackedArray.stub.php"/>
-    </stubs>
-
     <issueHandlers>
         <!-- Class is meant to be Unserialized by the extension only -->
         <PropertyNotSetInConstructor>
diff --git a/stubs/BSON/Document.stub.php b/stubs/BSON/Document.stub.php
deleted file mode 100644
index b1b3c60fb..000000000
--- a/stubs/BSON/Document.stub.php
+++ /dev/null
@@ -1,49 +0,0 @@
-<?php
-
-namespace MongoDB\BSON;
-
-/**
- * This stub file is temporary and can be removed when using Psalm 5
- *
- * @template TValue
- * @template-implements \IteratorAggregate<string, TValue>
- */
-final class Document implements \IteratorAggregate, \Serializable
-{
-    private function __construct() {}
-
-    final static public function fromBSON(string $bson): Document {}
-
-    final static public function fromJSON(string $json): Document {}
-
-    /** @param array|object $value */
-    final static public function fromPHP($value): Document {}
-
-    /** @return TValue */
-    final public function get(string $key) {}
-
-    /** @return Iterator<string, TValue> */
-    final public function getIterator(): Iterator {}
-
-    final public function has(string $key): bool {}
-
-    /** @return array|object */
-    final public function toPHP(?array $typeMap = null) {}
-
-    final public function toCanonicalExtendedJSON(): string {}
-
-    final public function toRelaxedExtendedJSON(): string {}
-
-    final public function __toString(): string {}
-
-    final public static function __set_state(array $properties): Document {}
-
-    final public function serialize(): string {}
-
-    /** @param string $serialized */
-    final public function unserialize($serialized): void {}
-
-    final public function __unserialize(array $data): void {}
-
-    final public function __serialize(): array {}
-}
diff --git a/stubs/BSON/Iterator.stub.php b/stubs/BSON/Iterator.stub.php
deleted file mode 100644
index cc8f699e4..000000000
--- a/stubs/BSON/Iterator.stub.php
+++ /dev/null
@@ -1,29 +0,0 @@
-<?php
-
-namespace MongoDB\BSON;
-
-/**
- * This stub file is temporary and can be removed when using Psalm 5
- *
- * @psalm-template TKey of int|string
- * @psalm-template TValue
- * $psalm-implements \Iterator<TKey, TValue>
- */
-final class Iterator implements \Iterator
-{
-    final private function __construct() {}
-
-    /** @return TValue */
-    final public function current() {}
-
-    /** @return TKey */
-    final public function key() {}
-
-    final public function next(): void {}
-
-    final public function rewind(): void {}
-
-    final public function valid(): bool {}
-
-    final public function __wakeup(): void {}
-}
diff --git a/stubs/BSON/PackedArray.stub.php b/stubs/BSON/PackedArray.stub.php
deleted file mode 100644
index 231a55019..000000000
--- a/stubs/BSON/PackedArray.stub.php
+++ /dev/null
@@ -1,40 +0,0 @@
-<?php
-
-namespace MongoDB\BSON;
-
-/**
- * This stub file is temporary and can be removed when using Psalm 5
- *
- * @template TValue
- * @template-implements \IteratorAggregate<int, TValue>
- */
-final class PackedArray implements \IteratorAggregate, \Serializable
-{
-    private function __construct() {}
-
-    final static public function fromPHP(array $value): PackedArray {}
-
-    /** @return TValue */
-    final public function get(int $index) {}
-
-    /** @return Iterator<int, TValue> */
-    final public function getIterator(): Iterator {}
-
-    final public function has(int $index): bool {}
-
-    /** @return array|object */
-    final public function toPHP(?array $typeMap = null) {}
-
-    final public function __toString(): string {}
-
-    final public static function __set_state(array $properties): PackedArray {}
-
-    final public function serialize(): string {}
-
-    /** @param string $serialized */
-    final public function unserialize($serialized): void {}
-
-    final public function __unserialize(array $data): void {}
-
-    final public function __serialize(): array {}
-}