Ember Labs' Kena: Bridge of Spirits debuted during a PS5 showcase, but it will be coming to PS4 as well. You can buy the current-gen version with confidence, though, as the studio says the upgrade to the PS5 version will be free.

The studio addressed a fan asking about next-gen upgrade, and confirmed that it will be free. It does come with one caveat: Ember says it hasn't finalized the time limit details yet. Some next-gen upgrades, like EA's Dual Entitlement for many sports games, only apply if you upgrade to the next-gen version within a certain window. Other games, like Control, have made waves by offering less generous upgrade programs.

The debut for Kena: Bridge of Spirits showed off a lush, vibrant world in the style of Studio Ghibli films. We saw combat with magic powers and a bow, as well as the assistance of a magical woodland spirit.

Yes!
We don't have the time limit details yet, but the upgrade is slated to be free!
— Kena: Bridge of Spirits (@emberlab) August 12, 2020

PlayStation competitor Xbox is offering next-gen upgrades as well with Smart Delivery. That program is voluntary for third-parties, but Microsoft says that all of its first-party games will use it to automatically determine the optimized version for your hardware.