diff --git a/crates/ruff_linter/src/rules/pyupgrade/rules/outdated_version_block.rs b/crates/ruff_linter/src/rules/pyupgrade/rules/outdated_version_block.rs
index 969220eb4481e..bcae8b3de3ddd 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/outdated_version_block.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/outdated_version_block.rs
@@ -44,6 +44,10 @@ use ruff_python_ast::PythonVersion;
 /// ## Options
 /// - `target-version`
 ///
+/// ## Fix safety
+/// This rule's fix is marked as unsafe because it will remove all code,
+/// comments, and annotations within unreachable version blocks.
+///
 /// ## References
 /// - [Python documentation: `sys.version_info`](https://docs.python.org/3/library/sys.html#sys.version_info)
 #[derive(ViolationMetadata)]