All iotty Smart Switches (Gen1 and Gen2) can be controlled from the iotty app which is free to download and use from the App or Google Play store.
Gen1 and Gen2 iotty Smart Switches can communicate with each other and toggle together in Automations like the Time Automation or Scene commands.
For 3-way and 4-way set-ups you can use a Gen1 and Gen2 iotty Smart Switch at separate locations of the same 3-way / 4-way. The Gen2 Switch with the Dimmer Module (purchased separately) attached should be placed at the control location (load to fixture) of the 3-way / 4-way set-up if you wish to have dimming of the lights.
Please note you will only be able to dim the shared lights at the control location of the Gen2 iotty Smart Switch where the Dimmer Module (purchased separately) is attached or from the iotty app once all 3-way / 4-way switches are registered and linked via Multiway Automation.