Migrating jQuery from 1.4 to 3.0

Question

I saw that jQuery has the jQuery-migrate script to safely upgrade jQuery. They have two jQuery-migrate repos:

1. https://github.com/jquery/jquery-migrate (for migrating to 3.x)
2. https://github.com/jquery/jquery-migrate/tree/1.x-stable (for migrating to 1.9)

Is it necessary to first migrate to 1.9 and then 3.x, or can I just include the first script in my website, and migrate to 3.x directly? Does the 3.x migration script not notify when APIs removed in 1.9 are used?

Answer 1

This is one of the links you provided: https://github.com/jquery/jquery-migrate. You can find this paragraph in the link you provided in your question:

NOTE: To upgrade to jQuery 3.0, you first need version 1.12.x or 2.2.x. If you're using an older version, first upgrade to one of these versions using jQuery Migrate 1.x, to resolve any compatibility issues. For more information about the changes made in jQuery 3.0, see the upgrade guide and blog post.

Since you want to migrate from jQuery 1.4 to 3.0, and based on what the official documentation says, you first need version 1.12.x or 2.2.x if you plan to use jQuery Migrate 1.x for resolving compatibility issues.