The Drupal security team will soon cease to provide security advisories, wavering the websites and cyber security.

Drupal 7 and Drupal 8 versions will get flagged as insecure in the 3rd party scans.

Drupal 8 already ended in November 2021.

Hence it is essential to plan and execute your Drupal 8 to Drupal 9 Migration or from any other version, before facing any security implications.

With the end of Drupal security support for the older versions, there would be many.

The expected release date for Drupal 10 is 14th December 2022.

Since Drupal8/9 works very much differently than Drupal7, the module structure has changed, the files type supported changed and Drupal API also changed. so with many modules which are available for download, you can find separate versions for Drupal7 and Drupal8/9.
But in the case of a custom module, you would like to upgrade your own module.

The Drupal Module Upgrader is a Drush command that helps you update your modules from Drupal 7 to Drupal 8.