When Phalcon 2 will be stable? Is there approximate date?
Not sure of they have a defined ETA. There are some bugs in the github queue that need to be answered. So when they have time to get through them seems to be the only acceptable answer.
i cant say for certain when it will be stable, but so far, things have been moving.
If you have knowledge of php/zephir you could try to establish your project based on phalcon 2, and help fix the bug as we go along. Of course that being so far, for all intend and purposes, i am basing a project based on 2.0 and nth is breaking yet. (fingers crossed)