How to Receive more than 20 Bytes from BLE connected device

Hello everyone !!!

I am new here in app inventor. I am working on a app which should receive more than 20 bytes from the BLE connected device.
I am able to receive only 20 Bytes. Please anyone can help me to solve the issue.
Also find my code here.

Try to change the MTU in the extension and in the device or send the information from 20 to 20 bytes.

Thanks for your response.
Can you suggest me an idea or link how to change MTU in the extension.

RequestMTU

This is not responding, can you tell me why?

Yeah Its working
Thanks a lot !!!

... you can try up to a maximum of 244 bytes.

Just be aware that adjusting the MTU needs to be supported on both the central and the peripheral. Otherwise, you will be restricted to 20 bytes because the payload size on the older BLE versions is fixed.

The data is coming from the device is 40 Bytes (20Bytes + 20Bytes). If I am changing the MTU to 40, the device is not responding (I can not change anything in the device). And without changing the MTU its responding only last 20 Bytes. So is there any way to get first 20 Bytes too.

We need to see the specification of the device - how do you know you are receiving the last 20 bytes but not the first 20?

I have checked in Serial Bluetooth app.

Have you got the specification?