Drupal 8's last minor release = Drupal 9? I have read about the planned release date of Drupal 9 is scheduled to be on June 3rd, 2020. I read this documentation about how to prepare a Drupal 8 site for Drupal 9:

Prepare a Drupal 8 site for Drupal 9

In the document it says:

"1. Keep Drupal core up to date. Drupal 8's last minor release will become Drupal 9."

Does it mean that when we update the Drupal 8 core to the last minor release of Drupal 8, it will automatically convert our site to use Drupal 9 and we don't have to radically change, migrate or redevelop our sites again in Drupal 9?

In summary, is Drupal 8 core's last minor release = Drupal 9?
Yes, upgrading from Drupal 8 to 9 is scheduled to be an incremental update from the last minor version of Drupal 8. 

It seems the main thing to consider is to remove any usage of deprecated functions to ensure a smooth upgrade. 


  Contributed project developers, as well as those maintaining custom integrations, should follow the deprecations when possible and use the latest APIs available. This means that when Drupal 9 is released they will have to make fewer changes to be compatible


https://www.drupal.org/core/deprecation