  We show that the outer automorphism groups of graph products of finitely
generated abelian groups satisfy the Tits alternative, are residually finite,
their so-called Torelli subgroups are finitely generated, and they satisfy a
dichotomy between being virtually nilpotent and containing a non-abelian free
subgroup that is determined by a graphical condition on the underlying labelled
graph.
  Graph products of finitely generated abelian groups simultaneously generalize
right-angled Artin groups (RAAGs) and right-angled Coxter groups (RACGs),
providing a common framework for studying these groups. Our results extend a
number of known results for the outer automorphism groups of RAAGs and/or RACGs
by a variety of authors, including Caprace, Charney, Day, Ferov, Guirardel,
Horbez, Minasyan, Vogtmann, Wade, and the current authors.
