title: Is there any need to change the migration file version to[6.0] while upgrading from rails 4.2 to rails6.0
body: <p>I upgraded my rails 4.2 project to rails5.2 and then now to rails6.0.
  One of my old migration file is:</p>
  <pre><code>class CreateLocations &lt; ActiveRecord::Migration
    def change
      create_table :locations do |t|
        t.string :name, :limit=&gt;100, :null=&gt;false      
        t.string :address1, :limit=&gt;60, :null=&gt;false
        t.string :address2, :limit=&gt;60, :null=&gt;false
        t.string :city, :limit=&gt;30, :null=&gt;false
        t.string :state, :limit=&gt;30, :null=&gt;false
        t.string :zip, :limit=&gt;15, :null=&gt;false     
        t.boolean :status
        t.references :user      
        t.timestamps
      end
    end
  end
  </code></pre>
  <p>Now, I updated the first line to:</p>
  <pre><code>class CreateLocations &lt; ActiveRecord::Migration[4.2]
  </code></pre>
  <p>Is it correct, or I need to give the new version [6.0] for existing old migration files.
  Please help</p>