Based on an analysis of the 3.1 firmware in bta 3, an employee of iH8sn0w, the tool which makes it possible to carry out jailbreak of the beta firmware, reveals that the expiration date of the latter (in test version) is scheduled for September 18.
The possibility of a bta 4 version of firmware 3.1 is unlikely for reasons that we can describe as historical.
Therefore, the arrival of 3.1 production firmware should be available a few days before the end of the latest beta version.
If September 17 is an assumption, we can say that version 3.1 will arrive around the middle of September.
We discuss it on the forum!