It's been a couple weeks since Update 1 for Windows 8.1 Developer's Preview was made available and HTC 8X and 8S users were left out of the release. Some HTC owners caught the update early and were able to install it, but shortly after Microsoft halted delivery of Update 1 due to found issues specific to HTC handsets.
HTC then went on record to tell HTC users that the company would continue to work to enable the 8X model to participate in future updates, but that the 8S is dead in the water and will no longer be supported for further Windows Phone 8.1 updates.
The issue for not being able to receive Update1 was reported to be related to HTC hardware drivers, but those specific drivers were never communicated.
Overnight, HTC owners were given a glimmer of hope that the company truly is working to solve problems. The HTC developed Attentive Phone app was updated. No new features appear to be included, so that might suggest that it's only supplied as a bug fix, and possibly preparing the way to be reintroduced as a supported platform for the Windows Phone 8.1 Developer Preview program. The Windows Phone store page for the app still shows the last update as being November 30, 2012, but it's just not been updated yet.
Of course, it could also be that HTC is simply bringing the Attentive Phone app version to the same level introduced in the just released HTC One M8 for Windows. Available immediately from Verizon, the new smartphone is receiving glowing reviews.
It's also not yet clear if only the 8S model will be receiving the update. 8X users are the only ones reporting the update being available. If it doesn't surface for the 8S that could also confirm that the Attentive Phone update is a fix for Update 1 for Windows Phone 8.1.
UPDATE: 8S users are also now reporting the update for the Attentive Phone app.
We'll have to wait and see if the updated Attentive Phone app is the fix for the Developer Preview program, but it's a good sign.