Newest Shopify API not in @shopify/koa-shopify-graphql-proxy (2021-01)

I'm setting up an app uninstall webhook for my Shopify app. My app in Shopify Developer is set to the latest API (2021-01).

However, when I register my webhook, there's no option for ApiVersion.January21. When I set it as January21 I get the following:

error: invalid JSON response body at https://test-sonder.myshopify.com/admin/api/undefined/graphql.json reason: Unexpected end of JSON input.

This is my server.js

 const { ApiVersion } = require('@shopify/koa-shopify-graphql-proxy');
 const registration = await registerWebhook({
          address: `${HOST}/webhooks/apps/uninstall`,
          topic: 'APP_UNINSTALLED',
          accessToken,
          shop,
          apiVersion: ApiVersion.January21
        });

My package.json

  {
  "dependencies": {
    "@koa/router": "^10.0.0",
    "@shopify/app-bridge-react": "^1.28.0",
    "@shopify/koa-shopify-auth": "^3.2.0",
    "@shopify/koa-shopify-graphql-proxy": "^4.1.0",
    "@shopify/koa-shopify-webhooks": "^2.6.0",
    "@shopify/polaris": "^5.12.0",
    "@zeit/next-css": "^1.0.1",
    "apollo-boost": "^0.4.9",
    "axios": "^0.21.1",
    "dotenv": "^8.2.0",
    "graphql": "^15.4.0",
    "isomorphic-fetch": "^3.0.0",
    "koa": "^2.13.1",
    "koa-router": "^8.0.8",
    "koa-session": "^6.1.0",
    "next": "^10.0.4",
    "ngrok": "^3.4.0",
    "react": "16.9.0",
    "react-apollo": "^3.1.5",
    "react-dom": "16.9.0",
    "react-html-parser": "^2.0.2",
    "react-player": "^2.7.2",
    "store-js": "^2.0.4"
  }
}