The latest Ask Cryptic posting for Star Trek Online has revealed some specifics coming in the Season Two: Ancient Enemies update.
New ships will include Galaxy class with saucer separation, Intrepid class with ablative armor and Defiant with cloaking device for Federation Vice Admirals , and for Klingon Dahar Masters the Fek’ihri class carrier. They also promise new ships coming with future expansions.
Klingons will also enjoy eight new missions "There are two that involve a house vs. house rivalry, two that involve invading Federation Space and four that involve the return of the ancient Klingon enemy – the Fek’ihri."
This image of some unfriendly looking aliens (the Fek'ihri maybe?), has been released recently too:
Ask Cryptic explores a few other questions too, check it out here.