Websima

Bots are special Telegram accounts designed to handle messages automatically. Telegram introduced that bots can be used as channel admins so they can send messages to channels if the bot has been assigned as channel administrator.
Channeller (Telegram Channel Admin) helps you to integrate Telegram bot and Telegram Channel to your WordPress site and send newsletter to channel members.
Features:
<ul>
<li>Send to Multiple Channels</li>
<li>Log Activities</li>
<li>Support Custom Post Types</li>
<li>Send Url, short Url or Custom Message</li>
<li>Send Photo to channel</li>
<li>Ability to send featured image</li>
<li>Ability to send post content</li>
<li>Send Text and Photo Messages to Groups </li>
<li>Supports Html Tags in Messages including a, b, strong, code, em and pre</li>
<li>Send Images from other sites</li>
<li>Send Video Files your WordPress site</li>
<li>Send Audio Files from your WordPress site</li>
<li>Set Default Settings for sending</li>
<li>Send Inline Buttons to channel</li>
<li>Send Messages as Future Posts</li>
</ul>
Notice: add @Channeller_Bot robot to your group to get the Group ID, your bot should be one of the Group members for sending messages.
how to create a new channel in Telegram (Persian): <a href="http://websima.com/%DA%A9%D8%A7%D9%86%D8%A7%D9%84-%D8%AA%D9%84%DA%AF%D8%B1%D8%A7%D9%85/" title="کانال تلگرام" rel="nofollow ugc">کانال تلگرام</a> 
Channeller Settings Help (Persian): <a href="http://websima.com/channeller" title="Channeller Plugin" rel="nofollow ugc">Channeller Plugin</a>

Channeller – Telegram Channel Administrator

Send Text, Link, Photo, Video and Audio Files from Wordpress to Telegram Channels and Groups using bots.

Bots are special Telegram accounts designed to handle messages automatically. Users can interact with bots by sending them command messages in private or group chats.
Teletter (Telegram Newsletter) helps you to integrate Telegram bot to your WordPress site and send newsletter to subscribers.
first of all you have to <a href="https://core.telegram.org/bots#botfather" rel="nofollow ugc">Create a New Bot</a> and get your Token API, then install the plugin, configure settings and send newsletters to subscribers. 
Persian Tutorial : <a href="http://websima.com/%D8%B1%D8%A8%D8%A7%D8%AA-%D8%AA%D9%84%DA%AF%D8%B1%D8%A7%D9%85/" rel="nofollow ugc">ربات تلگرام چیست</a>
Features:
<ul>
<li>Using getUpdates method, no need to https</li>
<li>Add Subscribers automatic to your subscribers list </li>
<li>Send newsletter by posting or updating new articles</li>
<li>Sending options including: URL, custom message or both of them</li>
<li>Limit number of new updates from Telegram API </li>
<li>Set currency time for get new updates (Hourly, Twice a day,Daily) </li>
<li>Get Updates Manually</li>
<li>Supporting Custom post types </li>
<li>Showing de active users (unsubscribers)</li>
<li>Translate Ready</li>
<li>Send Newsletter to all users or active users</li>
<li>Define admin users to send newsletter from your telegram account (Supporting Text or Image)</li>
<li>Send Image with Captions to All Users from Admin panel</li>
<li>Log all Messages Sent or Received on Admin panel</li>
<li>Admin users receive new subscribers and unsubscribers alarm on their telegram account </li>
</ul>
Note: this plugin is not supporting Webhook method now, we are working on it. 
Version 1.2 was Updated by using some codes from <a href="https://wordpress.org/plugins/telegram-bot/" rel="ugc">Telegram Bot</a> Plugin.
Visit Tutorials in Persian Language: <a href="http://websima.com/teletter" title="افزونه تلگرام" rel="nofollow ugc">افزونه تلگرام</a>

Teletter Telegram Newsletter

great plugin

Send Newsletter from Telegram Bot, user can subscribe to your site from Telegram Bot.

Channeller – Telegram Channel Administrator vs Teletter Telegram Newsletter