Direct answer: the Version 2.3 Exciting Cube Unboxing event runs from November 4 at 07:00 UTC until the November 18 maintenance. Use Cube Keys to accumulate mission progress and claim the official mission and final completion rewards.
What are the official rewards?
- Mission rewards: Cube Key ×285.
- Mission rewards: Regular Hero Draw Ticket ×10.
- Final completion rewards: Transcendence Engraving Stone ×15 and Transcendence Refinement Stone ×75.
What is the event requirement?
Complete the Main Quest “HP Recovery!”. Cube Keys used during the event accumulate toward mission progress; the final completion reward becomes claimable after the required progress is reached.
The listed quantities are maximum amounts from completing all missions. Rewards cannot be claimed after the event ends, and this notice does not change banner pity or ticket carryover rules.
Official source: A Joyful Moment - Exciting Cube Unboxing!.