diff --git a/UPGRADE-2.0.md b/UPGRADE-2.0.md
index c505fe6e9..da76671f1 100644
--- a/UPGRADE-2.0.md
+++ b/UPGRADE-2.0.md
@@ -27,3 +27,6 @@ UPGRADE FROM 1.x to 2.0
    removed. Use `--with-mongodb-system-libs` instead.
  * All classes that previously implemented the `Serializable` interface no
    longer implement this interface.
+ * The constructor of `MongoDB\BSON\UTCDateTime` no longer accepts a `string`
+   argument. To pass 64-bit integers on 32-bit platforms, use the
+   `MongoDB\BSON\Int64` class instead.
diff --git a/src/BSON/UTCDateTime.c b/src/BSON/UTCDateTime.c
index 568b06bdd..69299bafc 100644
--- a/src/BSON/UTCDateTime.c
+++ b/src/BSON/UTCDateTime.c
@@ -218,15 +218,9 @@ static PHP_METHOD(MongoDB_BSON_UTCDateTime, __construct)
 		case IS_DOUBLE:
 			php_phongo_utcdatetime_init_from_double(intern, Z_DVAL_P(milliseconds));
 			return;
-
-		case IS_STRING:
-			php_error_docref(NULL, E_DEPRECATED, "Creating a %s instance with a string is deprecated and will be removed in ext-mongodb 2.0", ZSTR_VAL(php_phongo_utcdatetime_ce->name));
-
-			php_phongo_utcdatetime_init_from_string(intern, Z_STRVAL_P(milliseconds), Z_STRLEN_P(milliseconds));
-			return;
 	}
 
-	phongo_throw_exception(PHONGO_ERROR_INVALID_ARGUMENT, "Expected integer or string, %s given", PHONGO_ZVAL_CLASS_OR_TYPE_NAME_P(milliseconds));
+	phongo_throw_exception(PHONGO_ERROR_INVALID_ARGUMENT, "Expected integer or object, %s given", PHONGO_ZVAL_CLASS_OR_TYPE_NAME_P(milliseconds));
 }
 
 static PHP_METHOD(MongoDB_BSON_UTCDateTime, __set_state)
diff --git a/src/BSON/UTCDateTime.stub.php b/src/BSON/UTCDateTime.stub.php
index 30c201706..68104fabb 100644
--- a/src/BSON/UTCDateTime.stub.php
+++ b/src/BSON/UTCDateTime.stub.php
@@ -9,7 +9,7 @@
 
 final class UTCDateTime implements UTCDateTimeInterface, \JsonSerializable, Type, \Stringable
 {
-    final public function __construct(int|string|float|\DateTimeInterface|Int64|null $milliseconds = null) {}
+    final public function __construct(int|float|\DateTimeInterface|Int64|null $milliseconds = null) {}
 
     final public function toDateTime(): \DateTime {}
 
diff --git a/src/BSON/UTCDateTime_arginfo.h b/src/BSON/UTCDateTime_arginfo.h
index 75a3862aa..e018df90c 100644
--- a/src/BSON/UTCDateTime_arginfo.h
+++ b/src/BSON/UTCDateTime_arginfo.h
@@ -1,8 +1,8 @@
 /* This is a generated file, edit the .stub.php file instead.
- * Stub hash: be638e28e19d1e9c040365f20b306b82dbfadf75 */
+ * Stub hash: e84944a701ed49a361960aac405d42a736037aa2 */
 
 ZEND_BEGIN_ARG_INFO_EX(arginfo_class_MongoDB_BSON_UTCDateTime___construct, 0, 0, 0)
-	ZEND_ARG_OBJ_TYPE_MASK(0, milliseconds, DateTimeInterface|MongoDB\\BSON\\Int64, MAY_BE_LONG|MAY_BE_STRING|MAY_BE_DOUBLE|MAY_BE_NULL, "null")
+	ZEND_ARG_OBJ_TYPE_MASK(0, milliseconds, DateTimeInterface|MongoDB\\BSON\\Int64, MAY_BE_LONG|MAY_BE_DOUBLE|MAY_BE_NULL, "null")
 ZEND_END_ARG_INFO()
 
 ZEND_BEGIN_ARG_WITH_RETURN_OBJ_INFO_EX(arginfo_class_MongoDB_BSON_UTCDateTime_toDateTime, 0, 0, DateTime, 0)
diff --git a/tests/bson/bson-utcdatetime-008.phpt b/tests/bson/bson-utcdatetime-008.phpt
index d39e02088..e8a9bb10f 100644
--- a/tests/bson/bson-utcdatetime-008.phpt
+++ b/tests/bson/bson-utcdatetime-008.phpt
@@ -5,17 +5,12 @@ MongoDB\BSON\UTCDateTime construction from 64-bit integer as string
 
 require_once __DIR__ . '/../utils/basic.inc';
 
-$utcdatetime = new MongoDB\BSON\UTCDateTime('1416445411987');
-
-var_dump($utcdatetime);
+echo throws(fn () => new MongoDB\BSON\UTCDateTime('1416445411987'), MongoDB\Driver\Exception\InvalidArgumentException::class), PHP_EOL;
 
 ?>
 ===DONE===
 <?php exit(0); ?>
---EXPECTF--
-Deprecated: MongoDB\BSON\UTCDateTime::__construct(): Creating a MongoDB\BSON\UTCDateTime instance with a string is deprecated and will be removed in ext-mongodb 2.0 in %s
-object(MongoDB\BSON\UTCDateTime)#%d (%d) {
-  ["milliseconds"]=>
-  string(13) "1416445411987"
-}
+--EXPECT--
+OK: Got MongoDB\Driver\Exception\InvalidArgumentException
+Expected integer or object, string given
 ===DONE===
diff --git a/tests/bson/bson-utcdatetime_error-003.phpt b/tests/bson/bson-utcdatetime_error-003.phpt
index 6eb1fa741..3b5afdcf3 100644
--- a/tests/bson/bson-utcdatetime_error-003.phpt
+++ b/tests/bson/bson-utcdatetime_error-003.phpt
@@ -26,20 +26,13 @@ echo throws(function() {
 ?>
 ===DONE===
 <?php exit(0); ?>
---EXPECTF--
-Deprecated: MongoDB\BSON\UTCDateTime::__construct(): Creating a MongoDB\BSON\UTCDateTime instance with a string is deprecated and will be removed in ext-mongodb 2.0 in %s
+--EXPECT--
 OK: Got MongoDB\Driver\Exception\InvalidArgumentException
-Error parsing "1234.5678" as 64-bit integer for MongoDB\BSON\UTCDateTime initialization
-
-Deprecated: MongoDB\BSON\UTCDateTime::__construct(): Creating a MongoDB\BSON\UTCDateTime instance with a string is deprecated and will be removed in ext-mongodb 2.0 in %s
+Expected integer or object, string given
 OK: Got MongoDB\Driver\Exception\InvalidArgumentException
-Error parsing "9223372036854775808" as 64-bit integer for MongoDB\BSON\UTCDateTime initialization
-
-Deprecated: MongoDB\BSON\UTCDateTime::__construct(): Creating a MongoDB\BSON\UTCDateTime instance with a string is deprecated and will be removed in ext-mongodb 2.0 in %s
+Expected integer or object, string given
 OK: Got MongoDB\Driver\Exception\InvalidArgumentException
-Error parsing "-9223372036854775809" as 64-bit integer for MongoDB\BSON\UTCDateTime initialization
-
-Deprecated: MongoDB\BSON\UTCDateTime::__construct(): Creating a MongoDB\BSON\UTCDateTime instance with a string is deprecated and will be removed in ext-mongodb 2.0 in %s
+Expected integer or object, string given
 OK: Got MongoDB\Driver\Exception\InvalidArgumentException
-Error parsing "18446744073709551615" as 64-bit integer for MongoDB\BSON\UTCDateTime initialization
+Expected integer or object, string given
 ===DONE===
diff --git a/tests/bson/bson-utcdatetime_error-004.phpt b/tests/bson/bson-utcdatetime_error-004.phpt
index 3ac92dea1..e4d123a43 100644
--- a/tests/bson/bson-utcdatetime_error-004.phpt
+++ b/tests/bson/bson-utcdatetime_error-004.phpt
@@ -21,7 +21,7 @@ foreach ($invalidValues as $invalidValue) {
 <?php exit(0); ?>
 --EXPECT--
 OK: Got MongoDB\Driver\Exception\InvalidArgumentException
-Expected integer or string, bool given
+Expected integer or object, bool given
 OK: Got MongoDB\Driver\Exception\InvalidArgumentException
-Expected integer or string, array given
+Expected integer or object, array given
 ===DONE===