diff --git a/6_3_Sending_a_Transaction_with_a_Locktime.md b/6_4_Sending_a_Transaction_with_a_Locktime.md
similarity index 99%
rename from 6_3_Sending_a_Transaction_with_a_Locktime.md
rename to 6_4_Sending_a_Transaction_with_a_Locktime.md
index 3d290ca..2e23822 100644
--- a/6_3_Sending_a_Transaction_with_a_Locktime.md
+++ b/6_4_Sending_a_Transaction_with_a_Locktime.md
@@ -1,4 +1,4 @@
-# 6.3: Sending a Transaction with a Locktime
+# 6.4: Sending a Transaction with a Locktime
 
 > **NOTE:** This is a draft in progress, so that I can get some feedback from early reviewers. It is not yet ready for learning.