The event is available for level 7 players and above. The version of the game should be 8.42.01

Collect event token - Letter - to progress.

Event walkthrough: 

1. Visit your friends, click on piles of letters outside their cities and get Stationery Knives and Letters.
2. Use Stationery Knives on obstacles in your city to get (with a certain chance) a pass to the mini-game, items for Express Delivery collection and Letters of Hope which are used to fly to special event destinations.
3. Letters of Hope can be also received while visiting Post Office. You can buy this building in the game shop during the event.
4. Fly to event destinations and get items for You've Got Mail collection. 
5. Get Golden Postage Stamp bonus for finishing Express Delivery collection to land mail guest planes. From mail guest planes you can get Obstacle-Free bonus which provides you with invulnerability to obstacles in the mini-game for 10 seconds.
6. For visiting Post Offices in your friends' cities get Delivery Date bonus which slows down your plane in the mini-game for 10 seconds.
7. Play the mini-game, get event tokens and other useful rewards. Passes to the mini-game can be obtained by clearing obstacles in your city and from special event destinations flights.

Tips:

• Post Office is available for purchase in the Store for 4000 coins.

You need the following items to build the Post Office:

Mail sorter: 3
Handheld Scanner: 3
Numerator: 3
Marking Machine: 3

The items can be obtained from event destinations flights.

• To land guest Mail Planes you need to activate the Golden Postage Stamp bonus. 

Event tasks:

Regular flights:

Special flights: