The Senior Operator Training Invitation Letter is a special item in Arknights.
- A training invitation exclusive to Senior Operators, offering accelerated promotion of their abilities to the Elite 2 level.
- Operators holding this letter are able to apply for short-term rush training; the Instructors will tailor the course according to the Operator's circumstances, helping them make rapid breakthroughs, unearth their own potential, and attain a decisive standard.
When used, the Senior Operator Training Invitation Letter will immediately promote a 5★ Operator of the player's choosing into Elite 2 for free.
Only 5★ Operators who are in at most Elite 1 maximum level can be immediately promoted to Elite 2 this way, and do note that if the player used it on Operators that had been raised already, the resources spent to do so will not be refunded!
The Senior Operator Training Invitation Letter is available as part of the Senior Operator Training Pack, which can be purchased in Packs Store during the Dossoles Holiday event (in the Global server) for US$19.99.