  Full LEP-I data collected by the ALEPH detector during 1991-1995 running are
analyzed in order to measure the $\tau$ decay branching fractions. The analysis
follows the global method used in the published study based on 1991-1993 data,
with several improvements, especially concerning the treatment of photons and
$\pi^0$'s. Extensive systematic studies are performed, in order to match the
large statistics of the data sample corresponding to 327148 measured and
identified $\tau$ decays. Preliminary values for the branching fractions are
obtained for the 2 leptonic channels and 11 hadronic channels defined by their
respective numbers of charged particles and $\pi^0$'s. Using previously
published ALEPH results on final states with charged and neutral kaons,
corrections are applied so that branching ratios for exclusive final states
without kaons are derived. Some physics implications of the results are given,
in particular concerning universality in the leptonic charged weak current,
isospin invariance in $a_1$ decays, and the separation of vector and
axial-vector components of the total hadronic rate.
