diff --git a/__tests__/utils/config.test.ts b/__tests__/utils/config.test.ts
index 40efe98e6..4aa8b6e44 100644
--- a/__tests__/utils/config.test.ts
+++ b/__tests__/utils/config.test.ts
@@ -89,8 +89,8 @@ describe('Configuration', () => {
 
   describe('Edge Cases', () => {
     it('should handle undefined values with default in get()', () => {
-      config.set('logLevel', undefined);
-      expect(config.get('logLevel', 'DEFAULT')).toBe('DEFAULT');
+      config.set('someKey', undefined);
+      expect(config.get('someKey', 'DEFAULT')).toBe('DEFAULT');
     });
 
     it('should treat keys as case-sensitive', () => {
diff --git a/src/channel/rpc_0_6.ts b/src/channel/rpc_0_6.ts
index f2d658e73..8874f50e8 100644
--- a/src/channel/rpc_0_6.ts
+++ b/src/channel/rpc_0_6.ts
@@ -1,4 +1,4 @@
-import { NetworkName, StarknetChainId } from '../global/constants';
+import { NetworkName, StarknetChainId, SYSTEM_MESSAGES } from '../global/constants';
 import { LibraryError, RpcError } from '../utils/errors';
 import {
   AccountInvocationItem,
@@ -450,10 +450,10 @@ export class RpcChannel {
         },
       });
 
-      logger.warn(
-        'You are using deprecated transaction version (V0,V1,V2)!, \n Update to the latest V3 transactions!',
-        { version: RPC.ETransactionVersion.V1, type: RPC.ETransactionType.INVOKE }
-      );
+      logger.warn(SYSTEM_MESSAGES.legacyTxWarningMessage, {
+        version: RPC.ETransactionVersion.V1,
+        type: RPC.ETransactionType.INVOKE,
+      });
     } else {
       // V3
       promise = this.fetchEndpoint('starknet_addInvokeTransaction', {
@@ -500,10 +500,10 @@ export class RpcChannel {
         },
       });
 
-      logger.warn(
-        'You are using deprecated transaction version (V0,V1,V2)!, \n Update to the latest V3 transactions!',
-        { version: RPC.ETransactionVersion.V1, type: RPC.ETransactionType.DECLARE }
-      );
+      logger.warn(SYSTEM_MESSAGES.legacyTxWarningMessage, {
+        version: RPC.ETransactionVersion.V1,
+        type: RPC.ETransactionType.DECLARE,
+      });
     } else if (isSierra(contract) && !isV3Tx(details)) {
       // V2 Cairo1
       promise = this.fetchEndpoint('starknet_addDeclareTransaction', {
@@ -524,10 +524,10 @@ export class RpcChannel {
         },
       });
 
-      logger.warn(
-        'You are using deprecated transaction version (V0,V1,V2)!, \n Update to the latest V3 transactions!',
-        { version: RPC.ETransactionVersion.V2, type: RPC.ETransactionType.DECLARE }
-      );
+      logger.warn(SYSTEM_MESSAGES.legacyTxWarningMessage, {
+        version: RPC.ETransactionVersion.V2,
+        type: RPC.ETransactionType.DECLARE,
+      });
     } else if (isSierra(contract) && isV3Tx(details)) {
       // V3 Cairo1
       promise = this.fetchEndpoint('starknet_addDeclareTransaction', {
@@ -579,10 +579,10 @@ export class RpcChannel {
         },
       });
 
-      logger.warn(
-        'You are using deprecated transaction version (V0,V1,V2)!, \n Update to the latest V3 transactions!',
-        { version: RPC.ETransactionVersion.V1, type: RPC.ETransactionType.DEPLOY_ACCOUNT }
-      );
+      logger.warn(SYSTEM_MESSAGES.legacyTxWarningMessage, {
+        version: RPC.ETransactionVersion.V1,
+        type: RPC.ETransactionType.DEPLOY_ACCOUNT,
+      });
     } else {
       // v3
       promise = this.fetchEndpoint('starknet_addDeployAccountTransaction', {
@@ -672,10 +672,10 @@ export class RpcChannel {
         max_fee: toHex(invocation.maxFee || 0),
       };
 
-      logger.warn(
-        'You are using deprecated transaction version (V0,V1,V2)!, \n Update to the latest V3 transactions!',
-        { version: invocation.version, type: invocation.type }
-      );
+      logger.warn(SYSTEM_MESSAGES.legacyTxWarningMessage, {
+        version: invocation.version,
+        type: invocation.type,
+      });
     } else {
       // V3
       details = {
diff --git a/src/channel/rpc_0_7.ts b/src/channel/rpc_0_7.ts
index fbc9bb8b8..1dbb1a971 100644
--- a/src/channel/rpc_0_7.ts
+++ b/src/channel/rpc_0_7.ts
@@ -1,4 +1,4 @@
-import { NetworkName, StarknetChainId } from '../global/constants';
+import { NetworkName, StarknetChainId, SYSTEM_MESSAGES } from '../global/constants';
 import { LibraryError, RpcError } from '../utils/errors';
 import {
   AccountInvocationItem,
@@ -455,10 +455,10 @@ export class RpcChannel {
         },
       });
 
-      logger.warn(
-        'You are using deprecated transaction version (V0,V1,V2)!, \n Update to the latest V3 transactions!',
-        { version: RPC.ETransactionVersion.V1, type: RPC.ETransactionType.INVOKE }
-      );
+      logger.warn(SYSTEM_MESSAGES.legacyTxWarningMessage, {
+        version: RPC.ETransactionVersion.V1,
+        type: RPC.ETransactionType.INVOKE,
+      });
     } else {
       // V3
       promise = this.fetchEndpoint('starknet_addInvokeTransaction', {
@@ -505,10 +505,10 @@ export class RpcChannel {
         },
       });
 
-      logger.warn(
-        'You are using deprecated transaction version (V0,V1,V2)!, \n Update to the latest V3 transactions!',
-        { version: RPC.ETransactionVersion.V1, type: RPC.ETransactionType.DECLARE }
-      );
+      logger.warn(SYSTEM_MESSAGES.legacyTxWarningMessage, {
+        version: RPC.ETransactionVersion.V1,
+        type: RPC.ETransactionType.DECLARE,
+      });
     } else if (isSierra(contract) && !isV3Tx(details)) {
       // V2 Cairo1
       promise = this.fetchEndpoint('starknet_addDeclareTransaction', {
@@ -529,10 +529,10 @@ export class RpcChannel {
         },
       });
 
-      logger.warn(
-        'You are using deprecated transaction version (V0,V1,V2)!, \n Update to the latest V3 transactions!',
-        { version: RPC.ETransactionVersion.V2, type: RPC.ETransactionType.DECLARE }
-      );
+      logger.warn(SYSTEM_MESSAGES.legacyTxWarningMessage, {
+        version: RPC.ETransactionVersion.V2,
+        type: RPC.ETransactionType.DECLARE,
+      });
     } else if (isSierra(contract) && isV3Tx(details)) {
       // V3 Cairo1
       promise = this.fetchEndpoint('starknet_addDeclareTransaction', {
@@ -584,10 +584,10 @@ export class RpcChannel {
         },
       });
 
-      logger.warn(
-        'You are using deprecated transaction version (V0,V1,V2)!, \n Update to the latest V3 transactions!',
-        { version: RPC.ETransactionVersion.V1, type: RPC.ETransactionType.DEPLOY_ACCOUNT }
-      );
+      logger.warn(SYSTEM_MESSAGES.legacyTxWarningMessage, {
+        version: RPC.ETransactionVersion.V1,
+        type: RPC.ETransactionType.DEPLOY_ACCOUNT,
+      });
     } else {
       // v3
       promise = this.fetchEndpoint('starknet_addDeployAccountTransaction', {
@@ -677,10 +677,10 @@ export class RpcChannel {
         max_fee: toHex(invocation.maxFee || 0),
       };
 
-      logger.warn(
-        'You are using deprecated transaction version (V0,V1,V2)!, \n Update to the latest V3 transactions!',
-        { version: invocation.version, type: invocation.type }
-      );
+      logger.warn(SYSTEM_MESSAGES.legacyTxWarningMessage, {
+        version: invocation.version,
+        type: invocation.type,
+      });
     } else {
       // V3
       details = {
diff --git a/src/global/config.ts b/src/global/config.ts
index ed39c3d5a..9c45f3f79 100644
--- a/src/global/config.ts
+++ b/src/global/config.ts
@@ -2,7 +2,7 @@ import { DEFAULT_GLOBAL_CONFIG } from './constants';
 
 type ConfigData = {
   [key: string]: any;
-};
+} & typeof DEFAULT_GLOBAL_CONFIG;
 
 class Configuration {
   private static instance: Configuration;
diff --git a/src/global/constants.ts b/src/global/constants.ts
index 12453dd2d..5b2a5fc32 100644
--- a/src/global/constants.ts
+++ b/src/global/constants.ts
@@ -91,7 +91,16 @@ export const HARDENING_BYTE = 128;
 export const HARDENING_4BYTES = 2147483648n;
 
 // Default initial global config
-export const DEFAULT_GLOBAL_CONFIG: { legacyMode: boolean; logLevel: LogLevel } = {
+export const DEFAULT_GLOBAL_CONFIG: {
+  legacyMode: boolean;
+  logLevel: LogLevel;
+} = {
   legacyMode: false,
   logLevel: 'INFO',
 };
+
+// Default system messages
+export const SYSTEM_MESSAGES = {
+  legacyTxWarningMessage:
+    'You are using a deprecated transaction version (V0,V1,V2)!\nUpdate to the latest V3 transactions!',
+};
diff --git a/src/global/logger.ts b/src/global/logger.ts
index d01cc0d9a..537c30d22 100644
--- a/src/global/logger.ts
+++ b/src/global/logger.ts
@@ -44,7 +44,7 @@ class Logger {
       try {
         formattedMessage += `\n${JSON.stringify(data, null, 2)}`;
       } catch (error) {
-        formattedMessage += `\n[JSON.stringify Error/Circular]`;
+        formattedMessage += `\n[JSON.stringify Error/Circular]: ${error}`;
       }
     }
 
@@ -145,14 +145,9 @@ class Logger {
    * @returns logs levels displayed on the configured LogLevel
    */
   public getEnabledLogLevels() {
-    const logLevelStringKeys = Object.keys(LogLevelIndex).filter(
-      (v) => Number.isNaN(Number(v)) && v !== 'OFF'
-    );
-    const logLevels = logLevelStringKeys.filter((s) => {
-      return this.shouldLog(LogLevelIndex[s as LogLevel]);
+    return Object.keys(LogLevelIndex).filter((s) => {
+      return this.shouldLog(LogLevelIndex[s as LogLevel]) && s !== 'OFF';
     });
-
-    return logLevels;
   }
 }