Yes, before send the request you have to establish the connection with the server, once the client is connected you can send the POST request and wait for the response from the server.
Ubidots let to their users send data over HTTP and TCP, please reference to the right documetation below:
To use HTTP, reference to the REST API reference. In this case the server will be
To use TCP, reference to this guide. In this case the server will be
The version of the library which used to use AT command is deprecated, you can reference to the new version of the library here.
As you know, we are a software company so we take care of any support present within the platform. Also, we provide to our users the hardware tools to get started with IoT like libraries and sample (provided "AS IS" without warranty); the propose of them is just to get start. To scalable solution or custom development, reach out to firstname.lastname@example.org with any questions.
All the best,