I found in the snapshot documentation the compatibility matrix and the following hint
Each snapshot can contain indices created in various versions of Elasticsearch.
This includes backing indices created for data streams. When restoring a snapshot, it must be
possible to restore all of these indices into the target cluster. If any indices in a snapshot were
created in an incompatible version, you will not be able restore the snapshot.
What does that mean for an index in detail?
Let's assume I created an index in es 6.x and took a snaphot of that index.
Now I updated my es to 7.x and restored that index via snapshot in es 7.x.
What happens if I now take a snapshot of that index (originally created on es 6.x) from the currently running es 7.x?
Is it possible to restore that snapshot now in es 8.x?
Means, is the index always marked with the created version or can the index be considered as created with es 7.x after it was restored in es 7.x?
Many thanks and regards