diff --git a/src/sysvars.cpp b/src/sysvars.cpp
index ad8970c..ba05f87 100644
--- a/src/sysvars.cpp
+++ b/src/sysvars.cpp
@@ -10,8 +10,8 @@
 #include <FS.h>
 #include <trace.h>
 
-#ifndef TRACE_SYSVARS
-# define TRACE_SYSVARS 0
+#ifndef DEBUG_SYSVARS
+# define DEBUG_SYSVARS 0
 #endif
 
 #if not defined(SYSVAR_FILE)
@@ -26,19 +26,19 @@ T svGetV(const String & name, const T deflt)
     File f = USEDFS.open(F(SYSVAR_FILE), "r");
     if (f) {
         JsonDocument doc;
-        DeserializationError err = deserializeJson(doc, f);
+        const DeserializationError err = deserializeJson(doc, f);
 
         if (err) {
-            TRACEPLUS(TRACE_SYSVARS, TRACE_ERROR, "SV: Deserialize error '%s'", err.c_str()); // wrong JSON file (malformed)
+            TRACEPLUS(DEBUG_SYSVARS, TRACE_ERROR, "SV: Deserialize error '%s'", err.c_str()); // wrong JSON file (malformed)
         } else {
             if (!doc.containsKey(name)) {
-                TRACEPLUS(TRACE_SYSVARS, TRACE_ERROR, "SV: Key '%s' not found", name.c_str());
+                TRACEPLUS(DEBUG_SYSVARS, TRACE_ERROR, "SV: Key '%s' not found", name.c_str());
             } else {
                 rv = doc[name].as<T>();
             }
         }
     } else {
-        TRACEPLUS(TRACE_SYSVARS, TRACE_ERROR, "SV: File not found");
+        TRACEPLUS(DEBUG_SYSVARS, TRACE_ERROR, "SV: File not found");
     }
     return rv;
 }
@@ -51,19 +51,19 @@ T svGetVFile(const String & name, const String & fname, const T deflt)
 
     if (f) {
         JsonDocument doc;
-        DeserializationError err = deserializeJson(doc, f);
+        const DeserializationError err = deserializeJson(doc, f);
 
         if (err) {
-            TRACEPLUS(TRACE_SYSVARS, TRACE_ERROR, "SV: Deserialize error '%s'", err.c_str()); // wrong JSON file (malformed)
+            TRACEPLUS(DEBUG_SYSVARS, TRACE_ERROR, "SV: Deserialize error '%s'", err.c_str()); // wrong JSON file (malformed)
         } else {
             if (!doc.containsKey(name)) {
-                TRACEPLUS(TRACE_SYSVARS, TRACE_ERROR, "SV: Key '%s' not found", name.c_str());
+                TRACEPLUS(DEBUG_SYSVARS, TRACE_ERROR, "SV: Key '%s' not found", name.c_str());
             } else {
                 rv = doc[name].as<T>();
             }
         }
     } else {
-        TRACEPLUS(TRACE_SYSVARS, TRACE_ERROR, "SV: File not found '%s'", fname.c_str());
+        TRACEPLUS(DEBUG_SYSVARS, TRACE_ERROR, "SV: File not found '%s'", fname.c_str());
     }
     return rv;
 }
@@ -86,7 +86,7 @@ int svSetV(const String & name, T value)
     File f = USEDFS.open(F(SYSVAR_FILE), "r");
 
     if (f) {
-        DeserializationError err = deserializeJson(doc, f);
+        const DeserializationError err = deserializeJson(doc, f);
         if (err) {
             res = SV_DESERIALIZE_ERROR; // wrong (malformed) JSON file
         }
@@ -123,7 +123,7 @@ int svSetVFile(const String & name, T value, const String & fname)
     File f = USEDFS.open(fname, "r");
 
     if (f) {
-        DeserializationError err = deserializeJson(doc, f);
+        const DeserializationError err = deserializeJson(doc, f);
         if (err) {
             res = SV_DESERIALIZE_ERROR; // wrong (malformed) JSON file
         }