How does one export a Pages doc to epub?

How do I export a Pages doc to epub-previous articles state you should choose Share > Export to epub-However when you try that you get a message stating that iworks has been discontinued? What now-I still do not know how to publish a Pages document to epub (post iworks so-to-speak) -please help? I have writtern a 30 pages mini-ebook and now want to publish it to epub (to enable me to publish it on iBooks, B&N and Amazon Kindle) but I do not know how to proceed?