This is about xbee-wifi the S6B modules running 2021 firmware. I configured them on the herokuapp.com with a dash board to remotely control relays with xbee digital outputs. It works fine. But after that, I thought I should explore how xbee-wifi works in transparent mode with AT command, like sending GET POST requests to web servers. I couldn't do any of that and wasted hours. Then I read a post about issues with 2021 firmware and downgraded to 2004, still no go. I eventually restored settings and got success. I think the herokuapp has set the cloud register to a value that is incompatible with transparent mode? I'll check later what got changed by herokuapp. I bet it was sending transparent data to device cloud. Does herokuapp really need that to work?