Are you sure you haven't missed the change in subtitle support in Kodi, where you have to add subtitle providers as separate addons ?
I might just have! I am using Kodi 16.1 on my laptop which seems to be the same version as the one installed in the TV Box. On my laptop i have installed the subtitle providers via the "Get more" option in the settings. I thought it would be the same for the LibreElec which is based on 16.1 as well.
Anyway, i will look the add-ons repository tomorrow and get back to you.
Thank you for your reply!!!!!!
edit: both the subtitles services and the PVR addons are on the settings-->addons waiting to be installed. Thank you again for giving me the hint