diff --git a/CMakeLists.txt b/CMakeLists.txt
index 81f609f5..8302179b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -41,6 +41,7 @@ option(CONFIG_IEC61850_CONTROL_SERVICE "Build with support for IEC 61850 control
 option(CONFIG_IEC61850_REPORT_SERVICE "Build with support for IEC 61850 reporting services" ON)
 option(CONFIG_IEC61850_LOG_SERVICE "Build with support for IEC 61850 logging services" ON)
 option(CONFIG_IEC61850_SETTING_GROUPS "Build with support for IEC 61850 setting group services" ON)
+option(CONFIG_IEC61850_SUPPORT_USER_READ_ACCESS_CONTROL "Allow user provided callback to control read access" ON)
 
 set(CONFIG_REPORTING_DEFAULT_REPORT_BUFFER_SIZE "65536" CACHE STRING "Default buffer size for buffered reports in byte" )
 
diff --git a/src/iec61850/common/iec61850_common.c b/src/iec61850/common/iec61850_common.c
index 8e17c05c..02156b8b 100644
--- a/src/iec61850/common/iec61850_common.c
+++ b/src/iec61850/common/iec61850_common.c
@@ -136,6 +136,8 @@ FunctionalConstraint_toString(FunctionalConstraint fc) {
         return "BR";
     case IEC61850_FC_LG:
         return "LG";
+    case IEC61850_FC_GO:
+        return "GO";
     default:
         return NULL;
     }
@@ -221,6 +223,12 @@ FunctionalConstraint_fromString(const char* fcString)
         return IEC61850_FC_NONE;
     }
 
+    if (fcString[0] == 'G') {
+        if (fcString[1] == 'O')
+            return IEC61850_FC_GO;
+        return IEC61850_FC_NONE;
+    }
+
     return IEC61850_FC_NONE;
 }
 
diff --git a/src/iec61850/inc/iec61850_common.h b/src/iec61850/inc/iec61850_common.h
index a41a7db4..b4f18b92 100644
--- a/src/iec61850/inc/iec61850_common.h
+++ b/src/iec61850/inc/iec61850_common.h
@@ -245,6 +245,8 @@ typedef enum eFunctionalConstraint {
     IEC61850_FC_BR = 16,
     /** Log control blocks */
     IEC61850_FC_LG = 17,
+    /** Goose control blocks */
+    IEC61850_FC_GO = 18,
 
     /** All FCs - wildcard value */
     IEC61850_FC_ALL = 99,
diff --git a/src/iec61850/server/mms_mapping/mms_mapping.c b/src/iec61850/server/mms_mapping/mms_mapping.c
index d36adc14..87919a7a 100644
--- a/src/iec61850/server/mms_mapping/mms_mapping.c
+++ b/src/iec61850/server/mms_mapping/mms_mapping.c
@@ -2481,8 +2481,8 @@ mmsReadAccessHandler (void* parameter, MmsDomain* domain, char* variableId, MmsS
                 fc = FunctionalConstraint_fromString(separator + 1);
 
                 if (fc == IEC61850_FC_BR || fc == IEC61850_FC_US ||
-                        fc == IEC61850_FC_MS || fc == IEC61850_FC_RP ||
-                        fc == IEC61850_FC_LG)
+                    fc == IEC61850_FC_MS || fc == IEC61850_FC_RP ||
+                    fc == IEC61850_FC_LG || fc == IEC61850_FC_GO)
                 {
                     return DATA_ACCESS_ERROR_SUCCESS;
                 }