diff --git a/RELNOTES.txt b/RELNOTES.txt
index 38816ab..7105bf0 100644
--- a/RELNOTES.txt
+++ b/RELNOTES.txt
@@ -811,3 +811,7 @@ Version 4.30.0 - 2024-12-09
 
 Version 4.30.1 - 2025-01-14
 * Added base64 decode input size check.
+
+Version 4.31.0 - 2025-04-25
+* Updated to support 603+.
+
diff --git a/include/osp/osperrno.h b/include/osp/osperrno.h
index c430de8..65864d4 100644
--- a/include/osp/osperrno.h
+++ b/include/osp/osperrno.h
@@ -124,6 +124,7 @@
 #define OSPC_ERR_TRAN_CALLED_FILTERING                  (OSPC_ERR_TRAN_MODULE + 515)
 #define OSPC_ERR_TRAN_GLOBAL_ERROR                      (OSPC_ERR_TRAN_MODULE + 516)
 #define OSPC_ERR_TRAN_DECLINE                           (OSPC_ERR_TRAN_MODULE + 517)
+#define OSPC_ERR_TRAN_NETWORK_BLOCKED                   (OSPC_ERR_TRAN_MODULE + 518)
 
 #define OSPC_ERR_SEC_MODULE                             12000
 #define OSPC_ERR_SEC_NOT_ENOUGH_SPACE_FOR_COPY          (OSPC_ERR_SEC_MODULE + 10)
diff --git a/include/osp/osplibversion.h b/include/osp/osplibversion.h
index b46536a..58aebed 100644
--- a/include/osp/osplibversion.h
+++ b/include/osp/osplibversion.h
@@ -20,7 +20,7 @@
 #define _OSPLIBVERSION_H
 
 #define OSP_CLIENT_TOOLKIT_VERSION_MAJOR    4
-#define OSP_CLIENT_TOOLKIT_VERSION_MINOR    30
+#define OSP_CLIENT_TOOLKIT_VERSION_MINOR    31
 #define OSP_CLIENT_TOOLKIT_VERSION_BUGFIX   0
 
 #endif /* _OSPLIBVERSION_H */
diff --git a/src/osputils.c b/src/osputils.c
index 6b00896..23104b1 100644
--- a/src/osputils.c
+++ b/src/osputils.c
@@ -165,6 +165,9 @@ int OSPPUtilGetErrorFromStatus(
         case 603:
             errorcode = OSPC_ERR_TRAN_DECLINE;
             break;
+        case 9603:
+            errorcode = OSPC_ERR_TRAN_NETWORK_BLOCKED;
+            break;
         case 999:
             errorcode = OSPC_ERR_TRAN_GENERIC_FAILURE;
             break;