diff --git a/dictionaries/CallMap.php b/dictionaries/CallMap.php
index 219e6372641..329decd3234 100644
--- a/dictionaries/CallMap.php
+++ b/dictionaries/CallMap.php
@@ -1793,27 +1793,10 @@
 'DateTime::setTimestamp' => ['static', 'unixtimestamp'=>'int'],
 'DateTime::setTimezone' => ['static', 'timezone'=>'DateTimeZone'],
 'DateTime::sub' => ['static', 'interval'=>'DateInterval'],
-'DateTimeImmutable::__construct' => ['void', 'time='=>'string'],
-'DateTimeImmutable::__construct\'1' => ['void', 'time'=>'?string', 'timezone'=>'?DateTimeZone'],
 'DateTimeImmutable::__set_state' => ['static', 'array'=>'array'],
 'DateTimeImmutable::__wakeup' => ['void'],
-'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],
-'DateTimeImmutable::createFromFormat' => ['static|false', 'format'=>'string', 'time'=>'string', 'timezone='=>'?DateTimeZone'],
 'DateTimeImmutable::createFromInterface' => ['self', 'object' => 'DateTimeInterface'],
-'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
-'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
-'DateTimeImmutable::format' => ['string', 'format'=>'string'],
 'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-'DateTimeImmutable::getOffset' => ['int'],
-'DateTimeImmutable::getTimestamp' => ['int|false'],
-'DateTimeImmutable::getTimezone' => ['DateTimeZone|false'],
-'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
-'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
-'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
-'DateTimeImmutable::setTime' => ['static|false', 'hour'=>'int', 'minute'=>'int', 'second='=>'int', 'microseconds='=>'int'],
-'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
-'DateTimeImmutable::setTimezone' => ['static|false', 'timezone'=>'DateTimeZone'],
-'DateTimeImmutable::sub' => ['static|false', 'interval'=>'DateInterval'],
 'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
 'DateTimeInterface::format' => ['string', 'format'=>'string'],
 'DateTimeInterface::getOffset' => ['int'],
diff --git a/dictionaries/CallMap_80_delta.php b/dictionaries/CallMap_80_delta.php
index afeb1bc4133..4200608e06a 100644
--- a/dictionaries/CallMap_80_delta.php
+++ b/dictionaries/CallMap_80_delta.php
@@ -41,10 +41,6 @@
       'old' => ['string|false', 'format'=>'string'],
       'new' => ['string', 'format'=>'string'],
     ],
-    'DateTimeImmutable::format' => [
-      'old' => ['string|false', 'format'=>'string'],
-      'new' => ['string', 'format'=>'string'],
-    ],
     'DateTimeZone::listIdentifiers' => [
       'old' => ['list<string>|false', 'timezoneGroup='=>'int', 'countryCode='=>'string|null'],
       'new' => ['list<string>', 'timezoneGroup='=>'int', 'countryCode='=>'string|null'],
diff --git a/dictionaries/CallMap_historical.php b/dictionaries/CallMap_historical.php
index a5c4875aa71..6df5d473acf 100644
--- a/dictionaries/CallMap_historical.php
+++ b/dictionaries/CallMap_historical.php
@@ -1055,26 +1055,9 @@
     'DateTime::setTimestamp' => ['static', 'unixtimestamp'=>'int'],
     'DateTime::setTimezone' => ['static', 'timezone'=>'DateTimeZone'],
     'DateTime::sub' => ['static', 'interval'=>'DateInterval'],
-    'DateTimeImmutable::__construct' => ['void', 'time='=>'string'],
-    'DateTimeImmutable::__construct\'1' => ['void', 'time'=>'?string', 'timezone'=>'?DateTimeZone'],
     'DateTimeImmutable::__set_state' => ['static', 'array'=>'array'],
     'DateTimeImmutable::__wakeup' => ['void'],
-    'DateTimeImmutable::add' => ['static', 'interval'=>'DateInterval'],
-    'DateTimeImmutable::createFromFormat' => ['static|false', 'format'=>'string', 'time'=>'string', 'timezone='=>'?DateTimeZone'],
-    'DateTimeImmutable::createFromMutable' => ['static', 'datetime'=>'DateTime'],
-    'DateTimeImmutable::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
-    'DateTimeImmutable::format' => ['string|false', 'format'=>'string'],
     'DateTimeImmutable::getLastErrors' => ['array{warning_count:int,warnings:array<int,string>,error_count:int,errors:array<int,string>}'],
-    'DateTimeImmutable::getOffset' => ['int'],
-    'DateTimeImmutable::getTimestamp' => ['int|false'],
-    'DateTimeImmutable::getTimezone' => ['DateTimeZone|false'],
-    'DateTimeImmutable::modify' => ['static', 'modify'=>'string'],
-    'DateTimeImmutable::setDate' => ['static|false', 'year'=>'int', 'month'=>'int', 'day'=>'int'],
-    'DateTimeImmutable::setISODate' => ['static|false', 'year'=>'int', 'week'=>'int', 'day='=>'int'],
-    'DateTimeImmutable::setTime' => ['static|false', 'hour'=>'int', 'minute'=>'int', 'second='=>'int', 'microseconds='=>'int'],
-    'DateTimeImmutable::setTimestamp' => ['static|false', 'unixtimestamp'=>'int'],
-    'DateTimeImmutable::setTimezone' => ['static|false', 'timezone'=>'DateTimeZone'],
-    'DateTimeImmutable::sub' => ['static|false', 'interval'=>'DateInterval'],
     'DateTimeInterface::diff' => ['DateInterval', 'datetime2'=>'DateTimeInterface', 'absolute='=>'bool'],
     'DateTimeInterface::format' => ['string', 'format'=>'string'],
     'DateTimeInterface::getOffset' => ['int'],
diff --git a/stubs/CoreImmutableClasses.phpstub b/stubs/CoreImmutableClasses.phpstub
index 405f89b43cd..23eb77bdb77 100644
--- a/stubs/CoreImmutableClasses.phpstub
+++ b/stubs/CoreImmutableClasses.phpstub
@@ -1,11 +1,105 @@
 <?php
 
-/**
- * @psalm-immutable
- */
 class DateTimeImmutable implements DateTimeInterface
 {
     public function __construct(string $datetime = "now", DateTimeZone $timezone = null) {}
+
+    /**
+     * @psalm-mutation-free
+     * @return static|false
+     */
+    public static function createFromFormat(string $format, string $datetime, ?DateTimeZone $timezone = null) {}
+
+    /**
+     * @psalm-mutation-free
+     *
+     * @param string $format
+     *
+     * @return ($format is non-empty-string ? non-empty-string : string)
+     */
+    public function format($format) {}
+
+    /**
+     * @psalm-mutation-free
+     * @return DateTimeZone
+     */
+    public function getTimezone() {}
+
+    /**
+     * @psalm-mutation-free
+     * @return int
+     */
+    public function getOffset() {}
+
+    /**
+     * @psalm-mutation-free
+     * @return int
+     */
+    public function getTimestamp() {}
+
+    /**
+     * @psalm-mutation-free
+     * @param bool $absolute
+     * @return DateInterval
+     */
+    public function diff(DateTimeInterface $targetObject, $absolute = false) {}
+
+    /**
+     * @psalm-mutation-free
+     * @return static|false
+     */
+    public function modify(string $modifier) {}
+
+    /**
+     * @psalm-mutation-free
+     * @return static
+     */
+    public function add(DateInterval $interval) {}
+
+    /**
+     * @psalm-mutation-free
+     * @return static|false this method can fail in case an {@see DateInterval} with relative
+     *                      week days is passed in.
+     *
+     * @see https://github.com/php/php-src/blob/534127d3b22b193ffb9511c4447584f0d2bd4e24/ext/date/php_date.c#L3157-L3160
+     */
+    public function sub(DateInterval $interval) {}
+
+    /**
+     * @psalm-mutation-free
+     * @return static
+     */
+    public function setTimezone(DateTimeZone $timezone) {}
+
+    /**
+     * @psalm-mutation-free
+     * @return static
+     */
+    public function setTime(int $hour, int $minute, int $second = 0, int $microsecond = 0) {}
+
+    /**
+     * @psalm-mutation-free
+     * @return static
+     */
+    public function setDate(int $year, int $month, int $day) {}
+
+    /**
+     * @psalm-mutation-free
+     * @return static
+     */
+    public function setISODate(int $year, int $week, int $dayOfWeek = 1) {}
+
+    /**
+     * @psalm-mutation-free
+     * @return static
+     */
+    public function setTimestamp(int $unixtimestamp) {}
+
+    /**
+     * @psalm-mutation-free
+     * @return static
+     */
+    public static function createFromMutable(DateTime $object) {}
 }
 
 /**
diff --git a/tests/MethodCallTest.php b/tests/MethodCallTest.php
index 843cce11941..62860e8f209 100644
--- a/tests/MethodCallTest.php
+++ b/tests/MethodCallTest.php
@@ -264,7 +264,6 @@ public static function main(): void {
             ],
             'dateTimeImmutableStatic' => [
                 '<?php
-                    /** @psalm-immutable */
                     final class MyDate extends DateTimeImmutable {}
 
                     $today = new MyDate();
@@ -273,7 +272,7 @@ final class MyDate extends DateTimeImmutable {}
                     $b = (new DateTimeImmutable())->modify("+3 hours");',
                 'assertions' => [
                     '$yesterday' => 'MyDate|false',
-                    '$b' => 'DateTimeImmutable',
+                    '$b' => 'DateTimeImmutable|false',
                 ],
             ],
             'magicCall' => [