According to the Hollywood Reporter Danny Strong has completed the script for Mockingjay Part 1.


Lionsgate has exercised its option for Danny Strong, who wrote the Emmy-winning HBO movie Game Change, to pen the script for the second part of the company’s adaptation of Mockingjay, the finale of the Hunger Games movie series. Strong already had written the script for Mockingjay, Part 1 and had a deal to write the script for the second part. But it was always contingent on the studio liking and approving his draft for Part 1.
Source: THR