Removed old browser compatibility

Vue 3 was built for speed and “modern” JavaScript. Backward compatibility for older browsers has been removed. Many internal functions used for reactivity now use native implementations by default (for example, the Proxy API). If you need to support an application in an outdated browser, you should consider staying with Vue 2, but fear not! There is an official plugin for Vue 2 to use the new Composition API, including the script setup syntax:

• Vue 2.7 includes it without plugins (https://blog.vuejs.org/posts/vue-2-7-naruto.html)
• If you are on Vue 2.6 or below, you can find the plugin here: https://github.com/vuejs/composition-api
• If you still want the speed of Vue 3, there is a special migration build that has almost the same API as Vue 2 (see https://v3-migration.vuejs.org/migration-build.html)
• Why remove old browsers’ compatibility? There are many reasons, including the following:
  • The global usage of older...