diff --git a/button-merchant/src/main/java/com/usebutton/merchant/Order.java b/button-merchant/src/main/java/com/usebutton/merchant/Order.java
index f998e2c..943d1a9 100644
--- a/button-merchant/src/main/java/com/usebutton/merchant/Order.java
+++ b/button-merchant/src/main/java/com/usebutton/merchant/Order.java
@@ -405,11 +405,12 @@ public Builder setEmail(String email) {
             }
 
             /**
-             * The SHA-256 hash of the transacting customer’s lowercase email, as a 64-character hex string.
-             * Note: The value of the e-mail address must be converted to lowercase before computing the hash.
-             * The hash itself may use uppercase or lowercase hex characters.
+             * The SHA-256 hash of the transacting customer’s lowercase email, as a 64-character
+             * hex string.
+             * Note: The value of the e-mail address must be converted to lowercase before
+             * computing the hash. The hash itself may use uppercase or lowercase hex characters.
              */
-            public Builder setEmailSha256(@Nullable String emailSha256) {
+            public Builder setEmailSha256(String emailSha256) {
                 this.emailSha256 = emailSha256;
                 return this;
             }