  We describe the new developments in version 4 of the public computer code
HiggsBounds. HiggsBounds is a tool to test models with arbitrary Higgs sectors,
containing both neutral and charged Higgs bosons, against the published
exclusion bounds from Higgs searches at the LEP, Tevatron and LHC experiments.
From the model predictions for the Higgs masses, branching ratios, production
cross sections and total decay widths - which are specified by the user in the
input for the program - the code calculates the predicted signal rates for the
search channels considered in the experimental data. The signal rates are
compared to the expected and observed cross section limits from the Higgs
searches to determine whether a point in the model parameter space is excluded
at 95% confidence level. In this document we present a modification of the
HiggsBounds main algorithm that extends the exclusion test in order to ensure
that it provides useful results in the presence of one or more significant
excesses in the data, corresponding to potential Higgs signals. We also
describe a new method to test whether the limits from an experimental search
performed under certain model assumptions can be applied to a different
theoretical model. Further developments discussed here include a framework to
take into account theoretical uncertainties on the Higgs mass predictions, and
the possibility to obtain the $\chi^2$ likelihood of Higgs exclusion limits
from LEP. Extensions to the user subroutines from earlier versions of
HiggsBounds are described. The new features are demonstrated by additional
example programs.
