From my experience, in Umbraco 15 MOST things are based of Guids and some functions and constants (for instance the Super User id) are depricated. But I also notice that not everything is yet guid based. As far as I know, this is the end goal, but we’re not there yet.
Yeah I noticed that as well Luuk!
Wonder when references using ID values are not longer supported (probably will take a few months / years).
Thanks for the help.