Olympus will release the new E-m1 firmware update on June 16. You can already see the details at olympus.co.uk/site/en/c/cameras_support/downloads/e_m1_download.html. And also the E-M5II will get a new version 1.2: olympus.co.uk/site/en/c/cameras_support/downloads/e_m5_mark_ii_downloads.html
P.S.: And also the GH4 will get a major firmware update later this month.
Thanks Nico and Sebi for sharing this!