Shelly2 is a nice product. mqtt is built in, but you also can change the firmware to Tasmota (personally, I use a fork from Stefan Bode which provides absolute positioning for rollershutters, though not with a shelly2 but a 2-gang SonoffT1)
Please be aware that there is an (already merged) issue about mqtt2 binding is not able to send rollershutter commands correct. The bugfix will be available in upcoming OH2.5-M2.
I received my Shelly2.5 device and already installed it. It works perfectly with the mobile app.
In Openhab (via paper ui) i´ve installed the addon “MQQT Binding (2.4.0)” and add a new thing (MQTT broker). I´ve revied many posts and videos to setup the device but i am not realy getting a result.
The thing is offline with a communication error. As a Host/IP i´ve set “localhost”, none secured connection, port: 1883, username: my email address which i used for the registration of the shelly app, password: same, certificate- and puplic key pinning active.
i also tried the IP address of the raspberry, of the shelly device and of the fritzbox…