Renewal of terrace slabs - existing substructure

Then just leave everything as it is. Just because laying on sand is "old-fashioned" doesn't mean it's wrong.

I just wanted to have that confirmed, since I had no experience with it so far. Who knows, maybe the gravel on top of the sand wasn't possible or something like that; sometimes the problem lies quite deep, which apparently is not the case here ;) Could someone please possibly recommend something about the separating fleece? I assume that you definitely should separate the sand from the gravel so that it doesn't mix or something like that.