RTFM
page 13
Determine the leaf offset by taking your leaf temperaturereading and subtracting your room temperature reading from it.Note that this can result in a negative number. Round the leafoffset to the nearest whole number and enter this figure intoyour VPD-enabled device under its settings.
I managed to install Google Play store on a Raspberry Pi 4 tablet for fun. Loaded the AC Infinity app. Now I can remote in from my desktop to check on my Koolatron while multitasking with RIU.