I have now had the Utopic OK (On Key) for a little while. The On Key works by cutting the end of a key and leaving it in the lock (on the inside). This works quite well, but unfortunately my type of lock will lock the side without key so that part is pointless. I might as well have no keyhole on the outside. The lock feels very well built, and the black version is acceptable to look at, it is no design feat, but it blends in so noone actually notices it is there.
The On Key version can be disassembled in the part that covers the existing lock that sticks out of the door. It would be very easy to 3D print new parts of that, so it can work with Scandinavian type locks or other. Additionally the On Key version would definitely be able to easily be modified to work with Scandinavian type dead bolts (without keys)
The Utopic is very narrow which is why I selected it in the first place. I have an outward going door with a very small space to fit a lock handle and the Utopic just fits. It is the smallest of the smart locks I have looked it. That part works (almost) perfect, I have angled the lock just a little bit and that works - this is only possible with the On Key version.
The most annoying this about the device is that on unlock it will ALWAYS hold the door latch open. Which means that on most doors it will open a little bit. So the device will OPEN the door not just unlock it. There is no setting to change this. (Contrary to i.e. Danalock)
The company will not share Bluetooth or connection information. They say a wifi to rf bridge will come later.
Using the RF bridge (if it can be a master device) is important as the battery lifetime should be greatly improved with RF only. In that mode the lock will disable Bluetooth all together.
The device does not work with Samsung Galaxy S10(x) devices for some stupid reason, they are working on that. It works just fine with Apple iPhone.
The app not great, but not bad either. It works. In the app there are two ways to lock the device: Lock and Fully lock. Lock only turns once, Fully lock turns until stop. This is stupid thing and it should just always fully lock.
The lock has an integrated non-replaceable battery that can be charged on the device (it is also possible to get a battery pack, though I have not see anywhere to purchase it, I guess one could be made from a powerbank).
The only home control integration device they have is a small device powered by a 3V coin cell battery that works by shorting wires. This is clearly the same device as a button remote control but $7 US more expensive. So buy that instead and just solder yourself (which you are going to anyway).
Despite the documentation and talks with the company the home control integration device in my experience only Locks and not Fully Locks which in some cases means “Not actually locked”. After multiple setups I have managed to make it lock every time.
On the bright side: The “homecontrol” device can very easily be soldered to a ESP8266 and can work Tasmota firmware out of the box. It can even be powered by the ESP since it runs 3V.
Unfortunately there is no feedback from the lock, neither in the app or obviously via the home control device.
The button remote control seems to have a LED and three buttons so maybe that can send Lock and Fully lock and maybe receive some feedback, but that is just speculation from a Amazon Picture.
If anyone is interested I have documented the conversion of the homecontrol device to ESP8266 with pictures and can do a writeup.