Alongside the new iPad Pro 11 and iPad Pro 12.9 Apple also introduced a second generation Pencil. In case it wasnt clear, the new tablets are not compatible with the old stylus and the new stylus isnt compatible with the old tablets.
A big part of that is charging the new Apple Pencil is charged wirelessly from the new iPad Pros while the old one plugged into the Lightning port (which, by the way, the new tablets do not have). The second-gen Pencil also attaches to the tablet with magnets, which triggers a pairing process.
There are other differences too. The new Pencil supports a double tap gesture that is used in apps. For example, it can switch between drawing and erasing. That solves one of the pain points of the original, but it also makes upgrading more expensive.
Not only do you need a new stylus, but the second-generation Apple Pencil is more expensive too. It costs $130/135 compared to $100/100 for the original.