Redmine

Indeed. Feature added in r2211.

The patch does not work for issue updates. I had to copy this block in MailHandler#receive_issue_update, just before issue.save!

    # custom fields
    issue.custom_field_values = issue.available_custom_fields.inject({}) do |h, c|
      if value = get_keyword(c.name, :override => true)
        h[c.id] = value
      end
      h
    end

It is copied from receive_issue. I tested it and it works fine.

I set this issue to Reopened because in the current revision (r2220) the bug is still there for MailHandler#receive_issue_update

r2211 was not supposed to do anything for issue updates. See #2702.