According to the recent rumors from SR4, Sony a7R II will be announced in mid May and start shipping in June.

Reminder: On April 23, 2015 Sony will announce a RX or A-mount cameras (or both) and the “best candidates” are the RX2 and A99 II followed by the A58, RX20 and RX100 m4.

Source:SR4

Read more Sony Camera Rumors