diff --git a/phpstan.neon b/phpstan.neon
index 8168a38..aa98928 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -1,9 +1,13 @@
 parameters:
-	customRulesetUsed: true
-	reportUnmatchedIgnoredErrors: false
-	# Ignore phpstan-drupal extension's rules.
-	ignoreErrors:
-		- '#\Drupal calls should be avoided in classes, use dependency injection instead#'
-		- '#Plugin definitions cannot be altered.#'
-		- '#Missing cache backend declaration for performance.#'
-		- '#Plugin manager has cache backend specified but does not declare cache tags.#'
+  # we don't set a level so that we check deprecations only, and
+  # not to highlight unknown classes which are from composer suggestions.
+  customRulesetUsed: true
+  reportUnmatchedIgnoredErrors: false
+  # Ignore phpstan-drupal extension's rules.
+  ignoreErrors:
+    - '#\Drupal calls should be avoided in classes, use dependency injection instead#'
+    - '#Plugin definitions cannot be altered.#'
+    - '#Missing cache backend declaration for performance.#'
+    - '#Plugin manager has cache backend specified but does not declare cache tags.#'
+    # new static() is a best practice in Drupal, so we cannot fix that.
+    - '#^Unsafe usage of new static#'