8 - Want to display the validation error message above the webform - Drupal Answers
![Drupal 9 Readiness [#3119395] | Drupal.org](https://www.drupal.org/files/issues/2020-03-12/error-before-patch.png "Drupal 9 Readiness [#3119395] | Drupal.org")
Drupal 9 Readiness [#3119395] | Drupal.org
Site Owner's Guide to a Smooth Drupal 9 Upgrade Experience
9.8.1. hook_form_alter() add submit and validate for existing form. | Drupal Book
A preview of the breaking changes in Drupal 9 | QED42
![Replace usages of the deprecated drupal_set_message() function [#2958415] | Drupal.org](https://www.drupal.org/files/issues/2018-04-04/after-applying-patch_1.png "Replace usages of the deprecated drupal_set_message() function [#2958415] | Drupal.org")
Replace usages of the deprecated drupal_set_message() function [#2958415] | Drupal.org
Eurelis.com - Drupal 9 : qu'attendre de Drupal 9 ?
Automate Drupal 9 upgrades
![Tips & Tricks] Drupal 8 & 9: Creating modal windows (pop-ups) with a form and to send a mail programmatically](https://makedrupaleasy.com/sites/default/files/styles/max_750x750/public/articles/2017/stat-office-definitive-guide-alexander-technique-google-chrome-2017-04-23-103255.png?itok=geNuTCwr "Tips & Tricks] Drupal 8 & 9: Creating modal windows (pop-ups) with a form and to send a mail programmatically")
Tips & Tricks] Drupal 8 & 9: Creating modal windows (pop-ups) with a form and to send a mail programmatically
GitHub - grasmash/drupal8to9-upgrade
![Drupal set message deprecated [#3099387] | Drupal.org](https://www.drupal.org/files/issues/2019-12-09/scmsg_errors.PNG "Drupal set message deprecated [#3099387] | Drupal.org")
Drupal set message deprecated [#3099387] | Drupal.org
Prepare for Drupal 9: stop using drupal_set_message()! | Gábor Hojtsy on Drupal
How to check your Drupal 8 site is compatible with 9 version
drupal_set_message の代わりは \Drupal::messenger()->addStatus() - 鼻
How to prepare your module for Drupal 9 | ADCI Solutions
Drupal 9 Contrib Module Readiness Report from April 2020 – mcdwayne
![Drupal 9 Deprecated Code Report - functions drupal_set_message(), Unicode::strtolower(), constant DATETIME_DATETIME_STORAGE_FORMAT, and class Drupal\simpletest\WebTestBase [#3130494] | Drupal.org](https://www.drupal.org/files/issues/2020-05-07/DCAT-patch-apply.png "Drupal 9 Deprecated Code Report - functions drupal_set_message(), Unicode::strtolower(), constant DATETIME_DATETIME_STORAGE_FORMAT, and class Drupal\simpletest\WebTestBase [#3130494] | Drupal.org")
Drupal 9 Deprecated Code Report - functions drupal_set_message(), Unicode::strtolower(), constant DATETIME_DATETIME_STORAGE_FORMAT, and class Drupal\simpletest\WebTestBase [#3130494] | Drupal.org
![Support render arrays for drupal_set_message() [#2505497] | Drupal.org](https://www.drupal.org/files/issues/Uses__attached_in_render_array_with_drupal_set_message_____Site-Install.png "Support render arrays for drupal_set_message() [#2505497] | Drupal.org")
Support render arrays for drupal_set_message() [#2505497] | Drupal.org
Urban's Drupal 9 Upgrade Path. At the Urban Institute, Drupal is our… | by Data@Urban | Medium
Drupal 9: Automated Deprecated Code Removal - A Proof of Concept | Pronovix
![Drupal 9 Deprecated Code Report [#3042822] | Drupal.org](https://www.drupal.org/files/issues/2019-04-15/Screen%20Shot%202019-04-15%20at%2011.21.28%20PM.png "Drupal 9 Deprecated Code Report [#3042822] | Drupal.org")
Drupal 9 Deprecated Code Report [#3042822] | Drupal.org
![Drupal 9 replace deprecated function drupal_set_message() [#3221131] | Drupal.org](https://www.drupal.org/files/issues/2021-08-23/3221131_after.png "Drupal 9 replace deprecated function drupal_set_message() [#3221131] | Drupal.org")
Drupal 9 replace deprecated function drupal_set_message() [#3221131] | Drupal.org
Get ready for Drupal 9 | Droptica Blog
