  Satisfiability modulo theories (SMT) solvers have throughout the years been
able to cope with increasingly expressive formulas, from ground logics to full
first-order logic modulo theories. Nevertheless, higher-order logic within SMT
is still little explored. One main goal of the Matryoshka project, which
started in March 2017, is to extend the reasoning capabilities of SMT solvers
and other automatic provers beyond first-order logic. In this preliminary
report, we report on an extension of the SMT-LIB language, the standard input
format of SMT solvers, to handle higher-order constructs. We also discuss how
to augment the proof format of the SMT solver veriT to accommodate these new
constructs and the solving techniques they require.
