docs: def queryset(self, request, queryset):
          """Filter based on whether an update (of any sort) is available."""
          if self.value() == '-1':
              return queryset.filter(latest_version__isnull=True)
          elif self.value() == '0':
              return (
                  queryset
                  .filter(
                      current_version__isnull=False,
                      latest_version__isnull=False,
                      latest_version=F('current_version')
                  )
              )
          elif self.value() == '1':
              return (
                  queryset
                  .filter(
                      current_version__isnull=False,
                      latest_version__isnull=False
                  ).exclude(
                      latest_version=F('current_version')
                  )
              )
          else:
              return queryset