They had started a poll on Tumblr. Whether they should 1. publish it today, but it could be buggy and then fixes will come gradually, 2. publish it in three days and then without bugs, or 3. in 2 parts.
The first option won and now they are trying to quickly fix a few bugs before publishing it.
Edit: The update is that they had a medical problem and now it delays, so now its the second option, so the release is in 2 days. For Information refer to the Restart Hearts Tumblr :)