From the Johns Hopkins University page:
It is possible that another flyby target can be found and reached with
New Horizons' remaining fuel supply. And after that? Another exciting
possibility is that we can dramatically augment New Horizons'
capabilities by uploading new observing and onboard data-reduction
software once the spacecraft's flyby ...
The hydrazine tank of New Horizon has an elastomeric diaphragm separating the liquid from the pressurizing gas helium within zero gravity. There are 16 thrusters with redundant plumbing to the tank.
The diaphragm prevents helium entering the plumbing, so all hydrazine within the tubes is trapped. If the elastic diaphragm does not fully ...