  xFitter is an open-source package that provides a framework for the
determination of the parton distribution functions (PDFs) of the proton for
many different kinds of analyses in Quantum Chromodynamics (QCD). It
incorporates experimental data from a wide range of experiments including
fixed-target, Tevatron, HERA, and LHC. xFitter version 2.0.0 has recently been
released, and offers an expanded set of tools and options. The new xFitter
2.0.0 program links to the APFEL code which has implemented generalized
matching conditions that enable the switch from $N_F$ to $N_F+1$ active flavors
at an arbitrary matching scale $\mu_m$. This enables us to generalize the
transition between a FFNS and a VFNS and essentially vary continuously between
the two schemes; in this sense the matching scale $\mu_m$ allows us to unify
the FFNS and VFNS in a common framework. This paper provides a brief overview
of xFitter with emphasis of these new features.
