On June 17 2016, The way Mega Dragons were obtained was changed due to the removal of gameplay boosting spells.
On August 3rd 2016, the Desert and Cavern elements were removed. Many dragon's names and elements were altered. The Desert, Cliff, and Soaring Dragons were removed completely, and the Mega Dragons were given unique names. Players were given huge compensations from park resets in the form of DragonCash and gems. In addition, they were given one free Wisteria and Deadwood Dragon as well as the dragons they had prior to 1.4.
On October 10th 2016, Mega Dragons were removed. Players received 3,000 for each mega dragon they had in their park prior to the 1.6 update. Each mega dragon was turned into the enchanted version of its non-mega counterpart. However, Backflip Studios has hinted the return of them in a future update when emailing BackFlip Support about the new update.