diff --git a/content/learn/book/migration-guides/0.4-0.5/_index.md b/content/learn/book/migration-guides/0.4-0.5/_index.md
index 4a90ce1fbe..dc50ecf358 100644
--- a/content/learn/book/migration-guides/0.4-0.5/_index.md
+++ b/content/learn/book/migration-guides/0.4-0.5/_index.md
@@ -292,3 +292,7 @@ layout(set = 0, binding = 0) uniform CameraViewProj {
 ### Diagnostics
 `PrintDiagnosticsPlugin` is now `LogDiagnosticsPlugin`.
 
+
+### System Ordering
+
+The parallel system executor has been redesigned. Systems that had implicit orderings might no longer run in the same order. For more detail on the new behavior, see [the release notes](/news/bevy-0-5#new-parallel-system-executor).