  We update and extend our previous work reconstructing the potential of a
quintessence field from current observational data. We extend the cosmological
dataset to include new supernova data, plus information from the cosmic
microwave background and from baryon acoustic oscillations. We extend the
modelling by considering Pad\'e approximant expansions as well as Taylor
series, and by using observations to assess the viability of the tracker
hypothesis. We find that parameter constraints have improved by a factor of
two, with a strengthening of the preference of the cosmological constant over
evolving quintessence models. Present data show some signs, though
inconclusive, of favouring tracker models over non-tracker models under our
assumptions.
