I just backed up through iTunes - it's still there, still works, no issues at all. I have iTunes 12.10.0.7
And I have no issues with the old iOS9 iPhone 4 with iTunes either - connects and works with it just fine.
When it goes, hopefully we CAN keep the old version.
Here's what Apple says:
https://edition.cnn.com/2019/06/06/t...rnd/index.html