“Pokémon Go” is having a bit of a resurgence. Players are spending an average of $2.5 million per day in the popular augmented reality app since it introduced Pokémon trading on June 19, according to market intelligence company Sensor Tower.

The app was generating approximately $1.8 million in daily revenue on average in the 60 days leading up to the update, Sensor Tower said. Since then, players have spent about $700,000 more each day. That’s a 39% increase over the previous two months.

Trading allows two people to swap Pokémon as long as they’re both level 10 and physically nearby each other. Each trade costs a certain amount of Stardust (the in-game currency). If a Pokémon is Legendary, Shiny, or not in one person’s Pokédex, the players must complete a Special Trade. Special Trades can only be done once per day and require the players to have a Friendship Level of Great Friend or above.

Friendship Level is the other big feature introduced in the June 19 update. Players can increase it by exchanging gifts or fighting in gyms together.

Now that summer is ending in the U.S., Sensor Tower said it’s worth watching to see what impact cooler months will have on spending. “Then again, Niantic has signaled that proper player versus player gameplay is inbound by the end of the year, something we’ve long held is what’s necessary to propel player spending back to the levels seen at the game’s launch,” said Sensor Tower head of mobile insights Randy Nelson. “With only four months left in 2018, we’ll know its effect soon enough.”