The EmojiOne image for U+1F996 T-REX shows it nearly upright. While this is a popular look for the dinosaur, it does not reflect current scientific understanding. "Canonizing" it in an emoji will help perpetuate the myth.
Seems like you forgot about this in the 4.0 update. The t-rex is still almost upright, when the correct posture should be the body almost parallel to the ground, like this.
from @salty-horse @ issue #536 in emojione repo.