My visa sponsor has informed me that there is a brand new requirement to renew a working visa: certification from the tax office that you have paid your taxes for the most recent annual period. I’m told that a receipt stub or copy of your return does not suffice.
I called the tax office today, and they confirmed that you can apply for this by mail or fax as well as in person. In person, you need to bring your ARC and passport. By mail or fax, you need to write a letter requesting the certificate, and include your ARC and passport number, your address in Chinese, and your signature (which must closely match that on your passport signature page). A photocopy of the passport signature page must also be attached.
(EDIT: It took a full week to arrive.)
I don’t know whether one can get this certification at the same time that one files taxes (I’ll try that next year) but I imagine so.