diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/abstract/gateway-connector-version-processor.abstract.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/abstract/gateway-connector-version-processor.abstract.ts
new file mode 100644
index 0000000000..1a1c4f05bc
--- /dev/null
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/abstract/gateway-connector-version-processor.abstract.ts
@@ -0,0 +1,36 @@
+import { GatewayConnector } from '@home/components/widget/lib/gateway/gateway-widget.models';
+
+export abstract class GatewayConnectorVersionProcessor<BasicConfig> {
+  gatewayVersion: number;
+  configVersion: number;
+
+  protected constructor(protected gatewayVersionStr: string, protected connector: GatewayConnector) {
+    this.gatewayVersion = this.parseVersion(this.gatewayVersionStr);
+    this.configVersion = this.parseVersion(connector.configVersion);
+  }
+
+  getProcessedByVersion(): BasicConfig {
+    if (this.isVersionUpdateNeeded()) {
+      return this.configVersion > this.gatewayVersion
+        ? this.getDowngradedVersion()
+        : this.getUpgradedVersion();
+    }
+
+    return this.connector.configurationJson as unknown as BasicConfig;
+  }
+
+  private isVersionUpdateNeeded(): boolean {
+    if (!this.gatewayVersion || !this.configVersion) {
+      return false;
+    }
+
+    return this.configVersion !== this.gatewayVersion;
+  }
+
+  private parseVersion(version: string): number {
+    return Number(version?.replace(/\./g, ''));
+  }
+
+  abstract getDowngradedVersion(): BasicConfig;
+  abstract getUpgradedVersion(): BasicConfig;
+}
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/abstract/mqtt-version-processor.abstract.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/abstract/mqtt-version-processor.abstract.ts
new file mode 100644
index 0000000000..2a7bea0e1b
--- /dev/null
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/abstract/mqtt-version-processor.abstract.ts
@@ -0,0 +1,76 @@
+import {
+  GatewayConnectorVersionProcessor
+} from '@home/components/widget/lib/gateway/abstract/gateway-connector-version-processor.abstract';
+import {
+  GatewayConnector,
+  MQTTBasicConfig, MQTTBasicConfig_v3_5_2,
+  MQTTLegacyBasicConfig,
+  RequestMappingData,
+  RequestType,
+} from '@home/components/widget/lib/gateway/gateway-widget.models';
+import { isEqual } from '@core/utils';
+import { MqttVersionMappingUtil } from '@home/components/widget/lib/gateway/utils/mqtt-version-mapping.util';
+
+export class MqttVersionProcessor extends GatewayConnectorVersionProcessor<MQTTBasicConfig> {
+  private readonly mqttRequestTypeKeys = Object.values(RequestType);
+
+  constructor(
+    protected gatewayVersionStr: string,
+    protected connector: GatewayConnector
+  ) {
+    super(gatewayVersionStr, connector);
+  }
+  getUpgradedVersion(): MQTTBasicConfig {
+    const {
+      connectRequests,
+      disconnectRequests,
+      attributeRequests,
+      attributeUpdates,
+      serverSideRpc
+    } = this.connector.configurationJson as MQTTLegacyBasicConfig;
+    let configurationJson = {
+      ...this.connector.configurationJson,
+      requestsMapping: MqttVersionMappingUtil.mapRequestsToUpgradedVersion({
+        connectRequests,
+        disconnectRequests,
+        attributeRequests,
+        attributeUpdates,
+        serverSideRpc
+      }),
+      mapping: MqttVersionMappingUtil.mapMappingToUpgradedVersion((this.connector.configurationJson as MQTTLegacyBasicConfig).mapping),
+    };
+
+    this.mqttRequestTypeKeys.forEach((key: RequestType) => {
+      const { [key]: removedKey, ...rest } = configurationJson as MQTTLegacyBasicConfig;
+      configurationJson = { ...rest } as any;
+    });
+
+    this.cleanUpConfigJson(configurationJson as MQTTBasicConfig_v3_5_2);
+
+    return configurationJson as MQTTBasicConfig;
+  }
+
+  getDowngradedVersion(): MQTTLegacyBasicConfig {
+    const { requestsMapping, mapping, ...restConfig } = this.connector.configurationJson as MQTTBasicConfig_v3_5_2;
+
+    const updatedRequestsMapping =
+      MqttVersionMappingUtil.mapRequestsToDowngradedVersion(requestsMapping as Record<RequestType, RequestMappingData[]>);
+    const updatedMapping = MqttVersionMappingUtil.mapMappingToDowngradedVersion(mapping);
+
+    return {
+      ...restConfig,
+      ...updatedRequestsMapping,
+      mapping: updatedMapping,
+    };
+  }
+
+  private cleanUpConfigJson(configurationJson: MQTTBasicConfig_v3_5_2): void {
+    if (isEqual(configurationJson.requestsMapping, {})) {
+      delete configurationJson.requestsMapping;
+    }
+
+    if (isEqual(configurationJson.mapping, [])) {
+      delete configurationJson.mapping;
+    }
+  }
+}
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-basic-config.abstract.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-basic-config.abstract.ts
index 12529d942f..072d8ba834 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-basic-config.abstract.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-basic-config.abstract.ts
@@ -17,24 +17,23 @@
 import { ControlValueAccessor, FormBuilder, FormGroup, ValidationErrors, Validator } from '@angular/forms';
 import { Subject } from 'rxjs';
 import { takeUntil } from 'rxjs/operators';
-import { isObject } from 'lodash';
 import {
   MappingType,
   MQTTBasicConfig,
-  MQTTLegacyBasicConfig,
   RequestMappingData,
   RequestMappingValue,
   RequestType
 } from '@home/components/widget/lib/gateway/gateway-widget.models';
 import { Directive, OnDestroy } from '@angular/core';
+import { isObject } from '@core/utils';
 
 @Directive()
-export abstract class AbstractMqttBasicConfigComponent implements ControlValueAccessor, Validator, OnDestroy {
+export abstract class AbstractMqttBasicConfigComponent<BasicConfig> implements ControlValueAccessor, Validator, OnDestroy {
 
   basicFormGroup: FormGroup;
   mappingTypes = MappingType;
   private destroy$ = new Subject<void>();
-  private onChange: (value: MQTTBasicConfig | MQTTLegacyBasicConfig) => void;
+  private onChange: (value: BasicConfig) => void;
   private onTouched: () => void;
 
   constructor(protected fb: FormBuilder) {
@@ -58,7 +57,7 @@ export abstract class AbstractMqttBasicConfigComponent implements ControlValueAc
     this.destroy$.complete();
   }
 
-  registerOnChange(fn: (value: MQTTBasicConfig | MQTTLegacyBasicConfig) => void): void {
+  registerOnChange(fn: (value: BasicConfig) => void): void {
     this.onChange = fn;
   }
 
@@ -102,6 +101,6 @@ export abstract class AbstractMqttBasicConfigComponent implements ControlValueAc
     });
   }
 
-  abstract writeValue(basicConfig: MQTTBasicConfig | MQTTLegacyBasicConfig): void;
-  protected abstract getMappedMQTTConfig(basicConfig: MQTTBasicConfig): MQTTBasicConfig | MQTTLegacyBasicConfig;
+  abstract writeValue(basicConfig: BasicConfig): void;
+  protected abstract getMappedMQTTConfig(basicConfig: MQTTBasicConfig): BasicConfig;
 }
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-basic-config.component.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-basic-config.component.ts
index c4ebadb03d..e2c9918179 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-basic-config.component.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-basic-config.component.ts
@@ -17,7 +17,7 @@
 import { Component, forwardRef, Input, TemplateRef, ChangeDetectionStrategy } from '@angular/core';
 import { NG_VALUE_ACCESSOR, NG_VALIDATORS } from '@angular/forms';
 import {
-  MQTTBasicConfig,
+  MQTTBasicConfig_v3_5_2,
   RequestMappingData,
   RequestMappingValue,
   RequestType
@@ -68,12 +68,12 @@ import {
     MappingTableComponent,
   ],
 })
-export class MqttBasicConfigComponent extends AbstractMqttBasicConfigComponent {
+export class MqttBasicConfigComponent extends AbstractMqttBasicConfigComponent<MQTTBasicConfig_v3_5_2> {
 
   @Input()
   generalTabContent: TemplateRef<any>;
 
-  writeValue(basicConfig: MQTTBasicConfig): void {
+  writeValue(basicConfig: MQTTBasicConfig_v3_5_2): void {
     const { broker, mapping = [], requestsMapping } = basicConfig;
     const editedBase = {
       workers: broker && (broker.maxNumberOfWorkers || broker.maxMessageNumberPerWorker) ? {
@@ -88,7 +88,7 @@ export class MqttBasicConfigComponent extends AbstractMqttBasicConfigComponent {
     this.basicFormGroup.setValue(editedBase, {emitEvent: false});
   }
 
-  protected getMappedMQTTConfig(basicConfig: MQTTBasicConfig): MQTTBasicConfig {
+  protected getMappedMQTTConfig(basicConfig: MQTTBasicConfig_v3_5_2): MQTTBasicConfig_v3_5_2 {
     let { broker, workers, mapping, requestsMapping  } = basicConfig || {};
 
     if (isDefinedAndNotNull(workers.maxNumberOfWorkers) || isDefinedAndNotNull(workers.maxMessageNumberPerWorker)) {
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-legacy-basic-config.component.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-legacy-basic-config.component.ts
index 92e4e5b4b5..2ca5eba000 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-legacy-basic-config.component.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/mqtt/basic-config/mqtt-legacy-basic-config.component.ts
@@ -17,7 +17,7 @@
 import { Component, forwardRef, Input, TemplateRef, ChangeDetectionStrategy } from '@angular/core';
 import { NG_VALUE_ACCESSOR, NG_VALIDATORS } from '@angular/forms';
 import {
-  MQTTBasicConfig,
+  MQTTBasicConfig_v3_5_2,
   MQTTLegacyBasicConfig,
   RequestMappingData,
   RequestMappingValue,
@@ -70,7 +70,7 @@ import {
     MappingTableComponent,
   ],
 })
-export class MqttLegacyBasicConfigComponent extends AbstractMqttBasicConfigComponent {
+export class MqttLegacyBasicConfigComponent extends AbstractMqttBasicConfigComponent<MQTTLegacyBasicConfig> {
 
   @Input()
   generalTabContent: TemplateRef<any>;
@@ -85,7 +85,7 @@ export class MqttLegacyBasicConfigComponent extends AbstractMqttBasicConfigCompo
       attributeUpdates = [],
       serverSideRpc = []
     } = basicConfig;
-    const updatedRequestMapping = MqttVersionMappingUtil.mapRequestsToNewestVersion({
+    const updatedRequestMapping = MqttVersionMappingUtil.mapRequestsToUpgradedVersion({
       connectRequests,
       disconnectRequests,
       attributeRequests,
@@ -97,7 +97,7 @@ export class MqttLegacyBasicConfigComponent extends AbstractMqttBasicConfigCompo
         maxNumberOfWorkers: broker.maxNumberOfWorkers,
         maxMessageNumberPerWorker: broker.maxMessageNumberPerWorker,
       } : {},
-      mapping: MqttVersionMappingUtil.mapMappingToNewestVersion(mapping) || [],
+      mapping: MqttVersionMappingUtil.mapMappingToUpgradedVersion(mapping) || [],
       broker: broker || {},
       requestsMapping: this.getRequestDataArray(updatedRequestMapping),
     };
@@ -105,7 +105,7 @@ export class MqttLegacyBasicConfigComponent extends AbstractMqttBasicConfigCompo
     this.basicFormGroup.setValue(editedBase, {emitEvent: false});
   }
 
-  protected getMappedMQTTConfig(basicConfig: MQTTBasicConfig): MQTTLegacyBasicConfig {
+  protected getMappedMQTTConfig(basicConfig: MQTTBasicConfig_v3_5_2): MQTTLegacyBasicConfig {
     let { broker, workers, mapping, requestsMapping  } = basicConfig || {};
 
     if (isDefinedAndNotNull(workers.maxNumberOfWorkers) || isDefinedAndNotNull(workers.maxMessageNumberPerWorker)) {
@@ -121,8 +121,8 @@ export class MqttLegacyBasicConfigComponent extends AbstractMqttBasicConfigCompo
 
     return {
       broker,
-      mapping: MqttVersionMappingUtil.mapMappingToLegacyVersion(mapping),
-      ...(MqttVersionMappingUtil.mapRequestsToLegacyVersion(requestsMapping as Record<RequestType, RequestMappingData[]>))
+      mapping: MqttVersionMappingUtil.mapMappingToDowngradedVersion(mapping),
+      ...(MqttVersionMappingUtil.mapRequestsToDowngradedVersion(requestsMapping as Record<RequestType, RequestMappingData[]>))
     };
   }
 }
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/dialog/add-connector-dialog.component.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/dialog/add-connector-dialog.component.ts
index d79a1d3fec..0168cf86af 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/dialog/add-connector-dialog.component.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/dialog/add-connector-dialog.component.ts
@@ -97,8 +97,15 @@ export class AddConnectorDialogComponent
     this.submitted = true;
     const value = this.connectorForm.getRawValue();
     if (value.useDefaults) {
-      this.getDefaultConfig(value.type).subscribe(({current, legacy, ...defaultConfig}: GatewayVersionedDefaultConfig) => {
-        value.configurationJson = (this.data.gatewayVersion ? current : legacy) ?? defaultConfig;
+      this.getDefaultConfig(value.type).subscribe((defaultConfig: GatewayVersionedDefaultConfig) => {
+        const gatewayVersion = this.data.gatewayVersion;
+        if (gatewayVersion) {
+          value.configVersion = gatewayVersion;
+        }
+        value.configurationJson = (gatewayVersion
+          ? defaultConfig[this.data.gatewayVersion]
+          : defaultConfig.legacy)
+          ?? defaultConfig;
         if (this.connectorForm.valid) {
           this.dialogRef.close(value);
         }
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-connectors.component.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-connectors.component.ts
index d7d412f6da..96e15a110f 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-connectors.component.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-connectors.component.ts
@@ -65,7 +65,9 @@ import { AddConnectorDialogComponent } from '@home/components/widget/lib/gateway
 import { debounceTime, filter, switchMap, take, takeUntil, tap } from 'rxjs/operators';
 import { ErrorStateMatcher } from '@angular/material/core';
 import { PageData } from '@shared/models/page/page-data';
-import { GatewayConnectorVersionMappingUtil } from './utils/gateway-connector-version-mapping.util';
+import {
+  GatewayConnectorVersionMappingUtil
+} from '@home/components/widget/lib/gateway/utils/gateway-connector-version-mapping.util';
 
 export class ForceErrorStateMatcher implements ErrorStateMatcher {
   isErrorState(control: FormControl | null): boolean {
@@ -247,7 +249,7 @@ export class GatewayConnectorComponent extends PageComponent implements AfterVie
 
     value.ts = Date.now();
 
-    return GatewayConnectorVersionMappingUtil.getMappedByVersion(value, this.gatewayVersion);
+    return value;
   }
 
   private updateData(reload: boolean = false): void {
@@ -741,7 +743,7 @@ export class GatewayConnectorComponent extends PageComponent implements AfterVie
       ...connector,
     };
 
-    connectorState.basicConfig = connectorState.configurationJson;
+    connectorState.basicConfig = GatewayConnectorVersionMappingUtil.getConfig(connectorState, this.gatewayVersion);
     this.initialConnector = connectorState;
     this.updateConnector(connectorState);
   }
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-widget.models.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-widget.models.ts
index 4770eeea23..38040f15d3 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-widget.models.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-widget.models.ts
@@ -124,21 +124,14 @@ export interface GatewayConnectorBase {
   configVersion?: string;
 }
 
-export type GatewayConnector = CurrentGatewayConnector | LegacyGatewayConnector;
-
-export interface CurrentGatewayConnector extends GatewayConnectorBase {
+export interface GatewayConnector extends GatewayConnectorBase {
   configurationJson: ConnectorBaseConfig;
   basicConfig?: ConnectorBaseConfig;
 }
 
-export interface LegacyGatewayConnector extends GatewayConnectorBase {
-  configurationJson: ConnectorLegacyBaseConfig;
-  basicConfig?: ConnectorLegacyBaseConfig;
-}
-
 export interface GatewayVersionedDefaultConfig {
-  legacy: LegacyGatewayConnector;
-  current: GatewayConnector;
+  legacy: GatewayConnector;
+  '3.5.1': GatewayConnector;
 }
 
 export interface DataMapping {
@@ -201,8 +194,6 @@ export type ConnectorMappingFormValue = DeviceConnectorMapping | RequestMappingF
 
 export type ConnectorBaseConfig = ConnectorBaseInfo | MQTTBasicConfig | OPCBasicConfig | ModbusBasicConfig;
 
-export type ConnectorLegacyBaseConfig = ConnectorBaseInfo | MQTTLegacyBasicConfig;
-
 export interface ConnectorBaseInfo {
   name: string;
   id: string;
@@ -210,7 +201,9 @@ export interface ConnectorBaseInfo {
   logLevel: GatewayLogLevel;
 }
 
-export interface MQTTBasicConfig {
+export type MQTTBasicConfig = MQTTBasicConfig_v3_5_2 | MQTTLegacyBasicConfig;
+
+export interface MQTTBasicConfig_v3_5_2 {
   mapping: ConverterConnectorMapping[];
   requestsMapping: Record<RequestType, RequestMappingData[] | RequestMappingValue[]> | RequestMappingData[] | RequestMappingValue[];
   broker: BrokerConfig;
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/utils/gateway-connector-version-mapping.util.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/utils/gateway-connector-version-mapping.util.ts
index 6a48b5e64b..ab9e393fee 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/utils/gateway-connector-version-mapping.util.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/utils/gateway-connector-version-mapping.util.ts
@@ -15,52 +15,20 @@
 ///
 
 import {
+  ConnectorBaseConfig,
   ConnectorType,
   GatewayConnector,
-  LegacyGatewayConnector,
 } from '@home/components/widget/lib/gateway/gateway-widget.models';
-import { MqttVersionMappingUtil } from './mqtt-version-mapping.util';
+import { MqttVersionProcessor } from '@home/components/widget/lib/gateway/abstract/mqtt-version-processor.abstract';
 
-export class GatewayConnectorVersionMappingUtil {
+export abstract class GatewayConnectorVersionMappingUtil {
 
-  static getMappedByVersion(connector: GatewayConnector, gatewayVersion: string): GatewayConnector {
-    switch (connector.type) {
+  static getConfig(connector: GatewayConnector, gatewayVersion: string): ConnectorBaseConfig {
+    switch(connector.type) {
       case ConnectorType.MQTT:
-        return this.getMappedMQTTByVersion(connector, gatewayVersion);
+        return new MqttVersionProcessor(gatewayVersion, connector).getProcessedByVersion();
       default:
-        return connector;
+        return connector.configurationJson as ConnectorBaseConfig;
     }
   }
-
-  private static getMappedMQTTByVersion(
-    connector: GatewayConnector | LegacyGatewayConnector,
-    gatewayVersion: string
-  ): GatewayConnector | LegacyGatewayConnector {
-    if (this.isVersionUpdateNeeded(gatewayVersion, connector.configVersion)) {
-      return this.isGatewayOutdated(gatewayVersion, connector.configVersion)
-        ? MqttVersionMappingUtil.getLegacyVersion(connector)
-        : MqttVersionMappingUtil.getNewestVersion(connector);
-    }
-    return connector;
-  }
-
-  private static isGatewayOutdated(gatewayVersion: string, configVersion: string): boolean {
-    if (!gatewayVersion || !configVersion) {
-      return false;
-    }
-
-    return this.parseVersion(configVersion) > this.parseVersion(gatewayVersion);
-  }
-
-  private static isVersionUpdateNeeded(configVersion: string, gatewayVersion: string): boolean {
-    if (!gatewayVersion || !configVersion) {
-      return false;
-    }
-
-    return this.parseVersion(configVersion) !== this.parseVersion(gatewayVersion);
-  }
-
-  private static parseVersion(version: string): number {
-    return Number(version?.replace(/\./g, ''));
-  }
 }
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/utils/mqtt-version-mapping.util.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/utils/mqtt-version-mapping.util.ts
index e32d020730..ffd517c3e9 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/utils/mqtt-version-mapping.util.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/utils/mqtt-version-mapping.util.ts
@@ -14,21 +14,16 @@
 /// limitations under the License.
 ///
 
-import { deleteNullProperties, isEqual } from '@core/utils';
+import { deleteNullProperties } from '@core/utils';
 import {
   AttributeRequest,
   ConnectorDeviceInfo,
   Converter,
   ConverterConnectorMapping,
   ConvertorType,
-  CurrentGatewayConnector,
-  GatewayConnector,
   LegacyConverter,
   LegacyConverterConnectorMapping,
-  LegacyGatewayConnector,
   LegacyRequestMappingData,
-  MQTTBasicConfig,
-  MQTTLegacyBasicConfig,
   RequestMappingData,
   RequestType,
   ServerSideRpc,
@@ -44,56 +39,9 @@ export class MqttVersionMappingUtil {
   static readonly mqttRequestMappingNewFields =
     ['attributeNameExpressionSource', 'responseTopicQoS', 'extensionConfig'];
 
-  static getNewestVersion(mqttConnector: GatewayConnector): CurrentGatewayConnector {
-    const {
-      connectRequests,
-      disconnectRequests,
-      attributeRequests,
-      attributeUpdates,
-      serverSideRpc
-    } = mqttConnector.configurationJson as MQTTLegacyBasicConfig;
-    let configurationJson = {
-      ...mqttConnector.configurationJson,
-      requestsMapping: this.mapRequestsToNewestVersion({
-          connectRequests,
-          disconnectRequests,
-          attributeRequests,
-          attributeUpdates,
-          serverSideRpc
-        }),
-      mapping: this.mapMappingToNewestVersion((mqttConnector.configurationJson as MQTTLegacyBasicConfig).mapping),
-    };
-
-    this.mqttRequestTypeKeys.forEach((key: RequestType) => {
-      const { [key]: removedKey, ...rest } = configurationJson as MQTTLegacyBasicConfig;
-      configurationJson = { ...rest } as any;
-    });
-
-    this.cleanUpConfigJson(configurationJson as MQTTBasicConfig);
-
-    return {
-      ...mqttConnector,
-      configurationJson
-    } as CurrentGatewayConnector;
-  }
-
-  static getLegacyVersion(mqttConnector: GatewayConnector): LegacyGatewayConnector {
-    const { requestsMapping, mapping, ...restConfig } = mqttConnector.configurationJson as MQTTBasicConfig;
-
-    const updatedRequestsMapping = this.mapRequestsToLegacyVersion(requestsMapping as Record<RequestType, RequestMappingData[]>);
-    const updatedMapping = this.mapMappingToLegacyVersion(mapping);
-
-    return {
-      ...mqttConnector,
-      configurationJson: {
-        ...restConfig,
-        ...updatedRequestsMapping,
-        mapping: updatedMapping,
-      },
-    } as LegacyGatewayConnector;
-  }
-
-  static mapMappingToNewestVersion(mapping: LegacyConverterConnectorMapping[] | ConverterConnectorMapping[]): ConverterConnectorMapping[] {
+  static mapMappingToUpgradedVersion(
+    mapping: LegacyConverterConnectorMapping[] | ConverterConnectorMapping[]
+  ): ConverterConnectorMapping[] {
     return mapping?.map(({ converter, topicFilter, subscriptionQos = 1 }) => {
       const deviceInfo = converter.deviceInfo ?? this.extractConverterDeviceInfo(converter);
 
@@ -109,7 +57,7 @@ export class MqttVersionMappingUtil {
     });
   }
 
-  static mapRequestsToNewestVersion(
+  static mapRequestsToUpgradedVersion(
     requestMapping: Record<RequestType,
       RequestMappingData[] | LegacyRequestMappingData[]>
   ): Record<RequestType, RequestMappingData[]> {
@@ -119,7 +67,7 @@ export class MqttVersionMappingUtil {
       }
 
       acc[key] = requestMapping[key].map(value => {
-        const newValue = this.mapRequestToNewest(value as LegacyRequestMappingData, key);
+        const newValue = this.mapRequestToUpgradedVersion(value as LegacyRequestMappingData, key);
 
         this.cleanUpOldFields(newValue as {});
 
@@ -130,7 +78,7 @@ export class MqttVersionMappingUtil {
     }, {}) as Record<RequestType, RequestMappingData[]>;
   }
 
-  static mapRequestsToLegacyVersion(
+  static mapRequestsToDowngradedVersion(
     requestsMapping: Record<RequestType, RequestMappingData[]>
   ): Record<RequestType, LegacyRequestMappingData[]> {
     return this.mqttRequestTypeKeys.reduce((acc, key) => {
@@ -161,11 +109,11 @@ export class MqttVersionMappingUtil {
     }, {}) as Record<RequestType, LegacyRequestMappingData[]>;
   }
 
-  static mapMappingToLegacyVersion(
+  static mapMappingToDowngradedVersion(
     mapping: ConverterConnectorMapping[]
   ): LegacyConverterConnectorMapping[] {
     return mapping?.map((converterMapping: ConverterConnectorMapping) => {
-      const converter = this.mapConverterToLegacy(converterMapping.converter);
+      const converter = this.mapConverterToDowngradedVersion(converterMapping.converter);
 
       this.cleanUpNewFields(converter as {});
 
@@ -173,7 +121,7 @@ export class MqttVersionMappingUtil {
     });
   }
 
-  private static mapConverterToLegacy(converter: Converter): LegacyConverter {
+  private static mapConverterToDowngradedVersion(converter: Converter): LegacyConverter {
     const { deviceInfo, ...restConverter } = converter;
 
     return converter.type !== ConvertorType.BYTES ? {
@@ -216,16 +164,6 @@ export class MqttVersionMappingUtil {
     return SourceType.CONST;
   }
 
-  private static cleanUpConfigJson(configurationJson: MQTTBasicConfig): void {
-    if (isEqual(configurationJson.requestsMapping, {})) {
-      delete configurationJson.requestsMapping;
-    }
-
-    if (isEqual(configurationJson.mapping, [])) {
-      delete configurationJson.mapping;
-    }
-  }
-
   private static extractConverterDeviceInfo(converter: LegacyConverter): ConnectorDeviceInfo {
     const deviceNameExpression = converter.deviceNameExpression
       || converter.deviceNameJsonExpression
@@ -250,7 +188,7 @@ export class MqttVersionMappingUtil {
     } : null;
   }
 
-  private static mapRequestToNewest(value, key: RequestType): RequestMappingData {
+  private static mapRequestToUpgradedVersion(value, key: RequestType): RequestMappingData {
     const deviceNameExpression = value.deviceNameJsonExpression || value.deviceNameTopicExpression || null;
     const deviceProfileExpression = value.deviceTypeTopicExpression || value.deviceTypeJsonExpression || 'default';
     const deviceProfileExpressionSource = deviceProfileExpression ? this.getTypeSourceByValue(deviceProfileExpression) : null;
diff --git a/ui-ngx/src/assets/metadata/connector-default-configs/mqtt.json b/ui-ngx/src/assets/metadata/connector-default-configs/mqtt.json
index 96ab233ef4..b3ba47215f 100644
--- a/ui-ngx/src/assets/metadata/connector-default-configs/mqtt.json
+++ b/ui-ngx/src/assets/metadata/connector-default-configs/mqtt.json
@@ -1,5 +1,5 @@
 {
-    "current": {
+    "3.5.1": {
         "broker": {
             "host": "127.0.0.1",
             "port": 1883,