Update UPGRADE-3.0.md

Co-authored-by: Hugo Alliaume <[email protected]>

Author: smnandre

UPGRADE-3.0.md

@@ -1,8 +1,6 @@
 # UPGRADE FROM `2.x` TO `3.0`
 
-Symfony UX follows Symfony's release system. This means that major
-versions (like `3.0`) offer the same functionality as their previous minor
-versions (like `2.x`), once all deprecations have been removed.
+Symfony UX follows Symfony's release process, 2.x and 3.0 have the same features, but Symfony UX 3.0 doesn't include any deprecated features. To upgrade, make sure to resolve all deprecation notices. Read more about this in the [Symfony documentation](https://symfony.com/doc/6.4/setup/upgrade_major.html#upgrade-major-symfony-deprecations).
 
 However, major versions may also introduce new features and improvements, and a
 bump in the required PHP or packages versions.