Let’s make it three replies for people that refuse to read!
You do not need to, you can just keep using the current app next to the new one 
To add to the prior post: just keep your Shelly devices on the pre-2.0 firmware to continue using the legacy app.
Should you move to the 2.0 firmware, you may also have to switch to the new app, as the currently released 2.0 firmware version does not play well will the legacy app.
That should only be required if you are using authentication: if you do not use authentication it should be fine.
New weather station Ecowitt WS90 can lose Zigbee connection and data stream stops, even after a simple Homey reboot (HP23).
The device is seemingly still available but no data is sent anymore.
This issue does seem to be with other platforms (HA, Mqtt) as well not just with Homey but I think a investigation may be helpful from different setups.
A device reboot command should also be available I assume, would be helpful actually.
There is a discussion also at Shelly community about this. https://community.shelly.cloud/topic/15061-shelly-ecowitt-ws90-stops-sending-zigbee-data-after-some-time/#findComment-63535
Any suggestions how to add the Outdoor Plug S Gen3?
The Plug S Gen3 was added without issues, but the outdoor version is not showing (it’s working on the Legacy app). Prepping for Christmas 
It is not listed on the app store page, so currently not supported. You can email Drenso to request support, but you can also just use the legacy app.
no support for shelly pro 4pm? 
You can send a request to Drenso (developer) for adding support for your device. Check their contact details in the first post or Homey app store.
Not sure why you use the ‘vomiting’ emoticon.
Will the Uni Plus be added to the app and if so is there an ETA?
Critical Bug: Shelly BLU Door/Window (SBDW-002C) contact status stuck on “Open” in Shelly Control App
Hi everyone,
I recently started migrating my devices from the legacy app to the new Shelly Control app, but I have run into a major issue with my Shelly BLU Door/Window sensors (SBDW-002C).
The contact alarm in the Shelly Control app is extremely unreliable and, in some cases, stops working entirely. While the contact state updates quickly and reliably in both the Legacy app and the local mobile app, the status inside the Shelly Control app remains permanently stuck on “Open”.
This is definitely not a physical mounting or magnet alignment issue, as it functions perfectly fine in the other apps.
Because many of my key automations—including my heating control—rely directly on the state of these door/window sensors, this bug effectively renders the entire Shelly Control app unusable for me until it is resolved.
Is anyone else experiencing this issue, or is a fix already in the works?
Come on @Mark_Dowling. The answer to your question is literally the post above yours…
You probably did not migrate your BLE proxy scripts.
What do you mean by that? The Door/Window sensor itself doesn’t have those settings/scripts.
As for the other devices that act as gateways (Shelly Plus 2PM, Shelly Plugs, etc.), Bluetooth gateway options are all active across the board. Plus, everything works completely fine in the mobile Shelly App on my smartphone.
With the exception of two Shelly Plug S Gen3 devices.
On those, it is active in the mobile app as well, but it cannot be enabled in the Shelly Control App. It constantly throws an error claiming it is already activated. However, when checking the settings again shortly after, it goes right back to showing “No”.
You might want to report this to Drenso directly, so they can look into this.
Double check: when migrating you did first remove the device from the Legacy app? So it is not connected to both the Shelly Control and Shelly Legacy app?
