diff --git a/migrations/20251107223530-convert-release-string-null-to-null.js b/migrations/20251107223530-convert-release-string-null-to-null.js
new file mode 100644
index 00000000..3266fad5
--- /dev/null
+++ b/migrations/20251107223530-convert-release-string-null-to-null.js
@@ -0,0 +1,33 @@
+/**
+ * Convert payload.release equal to string "null" into real null
+ * across all per-project events collections (events:{projectId})
+ */
+module.exports = {
+  async up(db) {
+    const collections = await db.listCollections().toArray();
+    const targetCollections = collections
+      .map(c => c.name)
+      .filter(name => name && name.startsWith('events:'));
+
+    console.log(`Found ${targetCollections.length} events collections to normalize "null" string to null`);
+
+    for (const name of targetCollections) {
+      const coll = db.collection(name);
+
+      try {
+        const result = await coll.updateMany(
+          { 'payload.release': 'null' },
+          { $set: { 'payload.release': null } }
+        );
+
+        console.log(`[${name}] matched=${result.matchedCount}, modified=${result.modifiedCount}`);
+      } catch (e) {
+        console.error(`[${name}] failed to convert "null" string to null:`, e);
+      }
+    }
+  },
+
+  async down() {
+    console.log('Down migration is not implemented: cannot reliably restore original "null" string values.');
+  },
+};