quaternion.slerpQuaternions is not a function

Questions
1

let quaternion=new THREE.Quaternion();
console.log(quaternion.slerpQuaternions);//output:undefined

The slerpQuaternions doesn’t exist in Quaternion.But THREE.JS docs explained it.

2

Quaternion.slerpQuaternions() was added with r127. Are you already using this version or a later one?

3

Thanks, didn’t notice the update.