I don't think that post is accurate, perhaps because (based on the RSS feed) it is from 2015.
> Telegram’s source code is not an SDK or a library. [--] But to be fair, the messaging app doesn’t state they have an SDK. All they did is put their source code in the open.
TDLib is that SDK.
Are we able to run our own servers with your lib?
Good question, refer to on-premise deployment section @https://mesibo.com,