I believe that the release of the fix will be soon though I have no idea how it will be marketed.
I have no insight into what was or wasn't said or promised initially, I just purchased the Z1 and used it until I was re-diagnosed for an APAP device.
I just returned from a 3 week trip to the wilderness of central Oregon (Ochoco National Forest) fighting a large forest fire. I used the Z1 Auto every night having it run through the water container of a F&P HC150 humidifier. I don't carry the humidifier - only the container to use as a muffler for the noise the Z1 produces through the tubing. The humidifier uses too much electricity to use on 12V and it is too bulky to pack. I love the small size of the unit and it does work well after figuring out a way to eliminate the noise the unit produces. While I was on this trip I received an email from HDM, the manufacturer of the Z1 Auto, advising me that their muffler, the QTube, is now available for purchase. It is $34.95 plus shipping. I'm not happy with HDM as they should be providing this muffler at no cost to their registered users of the Z1 Auto. We purchased this APAP in good faith that it was as quite as advertised but it is not and is a noisy device, as attested to by many disgruntled customers. In fact, HDM recently removed their discussion forum probably due to the number of complaints. At this time I will NOT recommend that anyone purchase anything from HDM due to their total lack of good will and service to their customers.