diff --git a/build.gradle b/build.gradle
index a2f119e..d5dd55a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -21,7 +21,7 @@ repositories {
     jcenter()
 }
 
-version = '2.3.1'
+version = '2.4.0'
 
 // coveralls plugin depends on xml format report
 
diff --git a/src/main/java/com/invoiced/entity/Customer.java b/src/main/java/com/invoiced/entity/Customer.java
index d0ff4e3..008a425 100644
--- a/src/main/java/com/invoiced/entity/Customer.java
+++ b/src/main/java/com/invoiced/entity/Customer.java
@@ -83,8 +83,7 @@ protected long getParentID() {
 	@JsonProperty("payment_terms")
 	public String paymentTerms;
 
-	@JsonInclude(JsonInclude.Include.NON_EMPTY)
-	@JsonProperty("payment_source")
+	@JsonProperty(value = "payment_source", access = JsonProperty.Access.WRITE_ONLY)
 	public PaymentSource paymentSource;
 
 	@JsonInclude(JsonInclude.Include.NON_EMPTY)