  The High Altitude Water Cherenkov (HAWC) high-energy {\gamma}-ray observatory
was completed in march 2015 in central Mexico. The detector, consisting of 300
water tanks, is currently being upgraded to improve its performance at
Multi-TeV energies, with a sparse array of small water Cherenkov tanks. It will
extend the instrumental area by a factor of 4, and enhance the sensitivity at
the highest energies. In this contribution, the current status of the
observatory is presented, as well as the coming upgrade. The electronics and
the readout system for the new sparse array of small water tanks are also
desrcibed, and results from simulations performed to optimize the performance
of the array are discussed.
