Yesterday I updated my two Intel HTPC machines (one Intel NUC and one older AMD based PC) without any real problems from OpenElec to LibreElec. And today I updated my Raspberry PI2 from OpenElec to LibreElec.
In case you have PVR add-on's installed you have to de-install the PVR and re-install it again from LibreElec respository. Then the PVR add-on works again. The settings were kept in my case.
Great job team and as a gratitude I donate some money to keep up the good work.