Most if not all VPS server providers worth their salt these days offer a full backup solution where you can simple restore to a previous backup is something goes wrong. But that doesn’t mean we should be complacent and just rely on the provider to all the work for us.
As you will have seen recently we have been doing a bit of server upgrading. At the core of this upgrade is Nginx and HTTP2 support.
Now if your starting from scratch I recommend upgrading Nginx before adding your sites, it just makes things easier, you wont need to remove Nginx first and reinstall.