diff --git a/src/main/resources/scripts/V3_4_0_1__fix_presence_confirmations.sql b/src/main/resources/scripts/V3_4_0_1__fix_presence_confirmations.sql
new file mode 100644
index 0000000..645380a
--- /dev/null
+++ b/src/main/resources/scripts/V3_4_0_1__fix_presence_confirmations.sql
@@ -0,0 +1,9 @@
+DELETE FROM presence_confirmations
+WHERE id NOT IN (
+    SELECT MIN(id)
+    FROM presence_confirmations
+    GROUP BY date, user_id
+);
+
+ALTER TABLE presence_confirmations
+ADD CONSTRAINT pk_presence_confirmations PRIMARY KEY (date, user_id);
\ No newline at end of file