Mongoose Error: "useCreateIndex" is not supported but documentation still has it

This is frustrating. No clues why I got this error while documentation still has it. Please help!

My code to connect MongoDB with mongoose.

const mongoose = require('mongoose');

const connectDB = async () => {
    try {
        const conn = await mongoose.connect(process.env.MONGO_URI, {
            useNewUrlParser: true,
            useCreateIndex: true,
            useUnifiedTopology: true
        });

        console.log(`MongoDB Connected: ${conn.connection.host}`.cyan.underline.bold);
    } catch (err) {
        console.log(`Error: ${err.message}`.red);
        process.exit(1);
    }

}

module.exports = connectDB;

Error: option usecreateindex is not supported

Documentation says useCreateIndex is the updated method.

https://mongoosejs.com/docs/deprecations.html#