Some update regarding the timing of the Unitary Patent and Unitary Patent Court is available from the official website of the Unitary Patent Court.
The provisional application phase would start end of spring 2017, with the agreement on UPC entering into force in December 2017. The sunrise period for opting out would then start early September 2017 (thus providing 3-month period for opting out before the Court becomes operation).
The above timetable is conditional and provided with the clear disclaimer that there are a number of factors that will dictate whether the above is achievable. The most important factors in meeting these dates are the required ratifications of the UPCA and accession to the Protocol on Provisional Application. If these are not achieved, the time-plan will be disrupted.