To have a code 19 you need :
  • At least 15 enclosures in the park
  • At least 10 of them that have not been escaped from
  • Fewer than 10 escaped creatures
And to have a certain rarity of creatures available for Code 19 you need a certain amount of cages or more that rarity in your park :
  • Common : 7
  • Rare : 6
  • Super rare : 6
  • Legendary : 4

If you're still not getting Code 19, please try to move dinosaurs currently stored in your Asset Repository to either island (Isla Nublar or Isla Sorna).