Is it possible to obtain the second addon of the Discoverer Outfit?

Question

As the question says. Is it already possible to get the full (with two addons) Discoverer Outfit? 

Answer 1

Yes, it will become possible to obtain the full outfit of the Discovery outfit with the implementation of the Summer Update 2022! Sources: Tibia Article and also confirmed in an Official CM Response

Please follow the Measuring Tibia Quest for more details but the 20 areas needed to discover are:

1. Ab'Dendriel
2. Carlin
3. Edron
4. Feyrist
5. Hrodmir
6. Kazordoon
7. Kilmaresh
8. Krailos
9. Marapur
10. Northern Darama
11. Oramond
12. Quirefang
13. Roshamuul
14. Southern Darama
15. Thais
16. Tiquanda
17. Vandura
18. Venore
19. Yalahar
20. Zao

Answer 2

Besides the reward received for completing subareas and areas, you can also receive the Discoverer Outfits and its two addons for completing 10, 15 and 20 areas, respectively. Note that since there are currently only 19 areas in the game, the reward for 20 areas is not obtainable yet, but will be in the future when new areas are added to the map.

Source: https://tibia.fandom.com/wiki/Measuring_Tibia_Quest

It's currently not possible to obtain the second addon of this outfit because there are only 19 locations. For second addon you need 20 locations.