The port has been stuck at 2.5.0 since 2016. Upstream 7.x is a rebar3
plugin that pulls in hex_core and verl, and the supported way to use it
is {project_plugins, [rebar3_hex]} fetched from hex.pm at build time.
rebar3 itself already vendors hex_core as r3_hex_* for fetching
dependencies.
Nothing in the tree depends on this port: a grep over every category
Makefile plus Mk/ turns up no consumer other than the port itself.
Bringing the port up to 7.2.0 instead would mean adding two new ports
(devel/erlang-hex_core and devel/erlang-verl, both pure Erlang with no
runtime dependencies) and converting this one from USES=erlang:rebar to
erlang:rebar3, with the {deps,...} entry patched out and ERL_LIBS
pointed at the installed copies so rebar3 does not try to reach hex.pm
from the build jail. That seems like poor value for a plugin that
consumers are expected to fetch themselves.
EXPIRATION_DATE is set six months out, 2027-02-28.