Method: channels.getForumTopicsByID

Parameters:

Name	Type	Required
channel	Username, chat ID, Update, Message or InputChannel	Optional
topics	Array of int	Yes

Return type: messages.ForumTopics

Can bots use this method: YES

MadelineProto Example (now async for huge speed and parallelism!):

if (!file_exists('madeline.php')) {
    copy('https://phar.madelineproto.xyz/madeline.php', 'madeline.php');
}
include 'madeline.php';

$MadelineProto = new \danog\MadelineProto\API('session.madeline');
$MadelineProto->start();

// PHP 8+ syntax, use an array on PHP 7.
$messages_ForumTopics = $MadelineProto->channels->getForumTopicsByID(channel: InputChannel, topics: [int, int], );