Good news for you BlackBerry 10 developers who were fearing the date of June 30th, the day your BlackBerry Dev Alpha device was set to brick (shut off) as the devices will have no longer have an expiry/shut off date.
The BlackBerry 10 Dev Alpha A hardware will continue to be officially unsupported and the BlackBerry 10 Dev Alpha B hardware will join those same ranks on June 30th, but if you want to continue to developing apps against those devices beyond that date, you’re welcome to do so.
For more info on the BlackBerry 10 Dev Alpha program and to view other FAQs, please visit the BlackBerry 10 Dev Alpha web page.
Source: BlackBerry Dev Blog