MiMOlite Device Handler issues under new hub and new ST app

I have been migrating from my V1 hub to my new V3 hub over the last week, and now trying to get the devices to work properly. It has reminded my how critical the ST system had become to the house and what a pain it is when things just stop being supported.

I use a MIMOlite to control my remote gate latch, triggered from the 7th button on my Inovelli switch. I use it to hold the power to latch for 3 seconds

SmartThings removed MIMOlite from the list of supported devices, so I got the device handler from the Fortrezz website. Unfortunately I cannot get it to workpropery. Whilst the settings show you can configure the length of time to the latch (upto 3 seconds). At the moment it works only as a switch.

I don’t know if this is a failure of the device handler / compatibility with the new hub and device handler or something I have done wrong with the setup. (I have not changed anything on the hardware, just went through an exclude and then include process.