  The upgrade of the Inner Tracking System (ITS) of ALICE (A Large Ion Collider
Experiment) will extend measurements of heavy-flavour hadrons and low-mass
dileptons to a lower transverse momentum than currently achieved and increase
the readout capabilities to incorporate the full interaction. Furthermore, the
tracking efficiency will be improved at low transverse momentum. To achieve
this, the new ALICE ITS is comprised of seven layers of a custom Monolithic
Active Pixel Sensor design known as ALPIDE, with a spatial resolution of
$5\,\mathrm{\mu m}$. The use of the ALPIDE-based detector design will reduce
the material budget to $0.35\%\,\mathrm{X_0}$ per layer for the innermost three
layers, and to $1.0\%\,\mathrm{X_0}$ per layer for the outermost four layers,
compared to $1.14\%\,\mathrm{X_0}$ per layer in the previous ITS. The
construction effort in numerous sites around the world has resulted in a fully
assembled and connected detector, which is currently undergoing on surface
commissioning before its installation in the ALICE cavern. This contribution
discusses the design and the current status of the commissioning of the new ITS
detector, including the methods used to characterise the detector and the
results obtained so far.
