Sorry, today the OpenBeta starts and - not a release date ! - perhaps at the end of the week... 
Better not give any ideas

Open Beta YSE 1.5.1 RC1 is much more robust than 1.5.0, but , as the name says, is a beta.
We (all YSE team) want to run the open beta until is bugfree, so we can provide to all users a very very robust 1.5.1.
It takes more time, is sure, but the final result is much better.
So, wait for RC1, but is
BETA.
(Anyway, if you have 1.5.0, you can't be worst

)
This version is aimed for test sites, not production sites....
Anyway, the announcement will have all important information about YSE 1.5.1 RC1.
Don't rush, it will be out in time

ja ne!