Kendall Jenner to Caitlyn -- Happy Father's Day ... You're Still the Same Soul

Kendall Jenner just posted a pretty touching Father's Day shout out to Caitlyn, telling her she's always been the same person ... her hero.

Kendall says, "My whole life this soul was my daddy and just because your appearance is different now doesn't mean you were any less of a father to me my entire life."

She ended by saying, "Happy Father's Day to the person who raised me, and taught me everything I know. My hero."