Gem::Specification.outdated_and_latest_version

# File tmp/rubies/ruby-3.0.5/lib/rubygems/specification.rb, line 1192
def self.outdated_and_latest_version
  return enum_for __method__ unless block_given?

  # TODO: maybe we should switch to rubygems' version service?
  fetcher = Gem::SpecFetcher.fetcher

  latest_specs(true).each do |local_spec|
    dependency =
      Gem::Dependency.new local_spec.name, ">= #{local_spec.version}"

    remotes, = fetcher.search_for_dependency dependency
    remotes  = remotes.map {|n, _| n.version }

    latest_remote = remotes.sort.last

    yield [local_spec, latest_remote] if
      latest_remote and local_spec.version < latest_remote
  end

  nil
end