  The RICH detectors of the LHCb experiment provide identification of hadrons
produced in high energy proton-proton collisions in the LHC at CERN over a wide
momentum range (2 to 100 GeV/c). Cherenkov light is collected on photon
detector planes sensitive to single photons. The RICH will be upgraded (in
2019) to read out every bunch crossing, at a rate of 40 MHz. The current hybrid
photon detectors (HPD) will be replaced with multi-anode photomultiplier tubes
(customisations of the Hamamatsu R11265 and the H12699 MaPMTs). These
8$\times$8 pixel devices meet the experimental requirements thanks to their
small pixel size, high gain, negligible dark count rate ($\sim$50 Hz/cm$^2$)
and moderate cross-talk. The measured performance of several tubes is reported,
together with their long-term stability. A new 8-channel front-end chip, named
CLARO, has been designed in 0.35 $\mu$m CMOS AMS technology for the MaPMT
readout. The CLARO chip operates in binary mode and combines low power
consumption (\hbox{$\sim$1 mW/Ch}), wide bandwidth (baseline restored in
$\leq$25 ns) and radiation hardness. A 12-bit digital register permits the
optimisation of the dynamic range and the threshold level for each channel and
provides tools for the on-site calibration. The design choices and the
characterization of the electronics are presented.
