diff --git a/changelogs/unreleased/gh-5522-vy-tx-isolation-level.md b/changelogs/unreleased/gh-5522-vy-tx-isolation-level.md
index df63925d312a81d439852e51af6c535d7cbc3b31..15d6a6fcfb1f6f749a448927941457a6b7676c73 100644
--- a/changelogs/unreleased/gh-5522-vy-tx-isolation-level.md
+++ b/changelogs/unreleased/gh-5522-vy-tx-isolation-level.md
@@ -1,5 +1,7 @@
 ## feature/vinyl
 
-* Added support of transaction isolation levels for the Vinyl engine.
-  The `txn_isolation` option passed to `box.begin()` now has the same
-  effect for Vinyl and memtx (gh-5522).
+* **[Breaking change]** Added support of transaction isolation levels for the
+  Vinyl engine. The `txn_isolation` option passed to `box.begin()` now has the
+  same effect for Vinyl and memtx. Note, this effectively changes the default
+  isolation level of Vinyl transactions from 'read-committed' to 'best-effort',
+  which may cause more conflicts (gh-5522).