diff --git a/CHANGELOG.md b/CHANGELOG.md
index 85ccc02..21f0bc8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog
 
+# v0.15.1
+- Fix: Remove default null param on `PayUmaInvoice` graphql
+
 # v0.15.0
 - Add `is_uma` and `is_lnurl` to the Invoice object and `RELEASE_PAYMENT_PREIMAGE` webhook data.
 - Add extra params to `CreateUmaInvoice` and `PayUmaInvoice` for analytics
diff --git a/README.md b/README.md
index 2f694d4..ad84b7a 100644
--- a/README.md
+++ b/README.md
@@ -1,9 +1,9 @@
-# Lightspark Go SDK - v0.15.0
+# Lightspark Go SDK - v0.15.1
 
 The Lightspark Go SDK provides a convenient way to interact with the Lightspark services from applications written in
 the Go.
 
-**_WARNING: This SDK is in version 0.14.0 (active development). It means that its APIs may not be fully stable. Please
+**_WARNING: This SDK is in version 0.15.1 (active development). It means that its APIs may not be fully stable. Please
 expect that changes to the APIs may happen until we move to v1.0.0._**
 
 ## Documentation
diff --git a/scripts/pay_uma_invoice.go b/scripts/pay_uma_invoice.go
index e876d9c..28a75e4 100644
--- a/scripts/pay_uma_invoice.go
+++ b/scripts/pay_uma_invoice.go
@@ -10,7 +10,7 @@ mutation PayUmaInvoice(
     $timeout_secs: Int!
     $maximum_fees_msats: Long!
     $amount_msats: Long
-    $sender_hash: String = null
+    $sender_hash: String
 ) {
     pay_uma_invoice(input: {
         node_id: $node_id
diff --git a/version.go b/version.go
index 1446727..d6d733d 100644
--- a/version.go
+++ b/version.go
@@ -1,3 +1,3 @@
 package lightspark
 
-const VERSION = "0.15.0"
+const VERSION = "0.15.1"