Matter 1.4/1.4.1 Gap Analysis for Tasmota Implementation

Executive Summary

This document analyzes the gaps between Tasmota's current Matter implementation and the Matter 1.4/1.4.1 specification. The current implementation appears to target Matter 1.0/1.1 with some 1.2 features.

Current Implementation Status

Version Indicators

• DataModelRevision: Returns 17 (Matter 1.2 - Basic Information cluster attribute 0x0000)
• InteractionModelRevision: Returns 11 (Matter 1.2+ - in IM messages)
• Cluster Revisions: Various, ranging from 1-7 depending on cluster

Supported Device Types

Supported Clusters

Matter 1.4 New Features - Gap Analysis

1. New Device Types (Matter 1.4)

2. New Clusters (Matter 1.4)

3. Protocol Enhancements (Matter 1.4/1.4.1)

4. Security Updates

Detailed Gap Analysis

HIGH PRIORITY Gaps

1. Energy Measurement Clusters Missing

Tasmota has extensive energy monitoring capabilities (via PZEM, HLW8012, etc.) but these are not exposed via Matter. This is a significant gap since Matter 1.4 specifically adds energy clusters.

Missing Clusters:

• Electrical Power Measurement (0x0090)
• Electrical Energy Measurement (0x0091)

Recommendation: Create new plugin types:

• Matter_Plugin_Sensor_Power.be
• Matter_Plugin_Sensor_Energy.be

2. Thermostat Cluster Not Implemented

The cluster revision table references Thermostat (0x0201) but no plugin implements it.

Impact: Cannot expose Tasmota thermostat functionality to Matter controllers.

MEDIUM PRIORITY Gaps

3. ICD (Intermittently Connected Device) Support

Status: ✅ IMPLEMENTED (Base SIT mode per Matter 1.4.1 spec)

The ICD Management Cluster (0x0046) is always enabled with base SIT (Short Idle Time) mode, appropriate for mains-powered WiFi devices.

Implemented Attributes (per spec section 9.17.6):

• IdleModeDuration (0x0000) - 1 second (minimum per spec)
• ActiveModeDuration (0x0001) - 300ms (spec default)
• ActiveModeThreshold (0x0002) - 300ms (spec default)

Not Implemented (require optional features):

• ICDCounter, ClientsSupportedPerFabric, RegisteredClients - require CIP feature
• OperatingMode - requires LITS feature
• UserActiveModeTriggerHint/Instruction - require UAT feature

Cluster Configuration:

• Revision: 3 (Matter 1.4.1)
• Feature Map: 0x00 (no optional features)

mDNS Advertisement:

• SII=500ms, SAI=300ms (spec defaults)
• ICD key not advertised (per spec: only for LITS-capable devices)

Impact: Controllers know the device is always reachable with standard MRP timing.

4. Power Source Cluster Missing

No implementation of Power Source cluster (0x002F) which is important for:

• Battery level reporting
• Power source type indication
• Wired/battery status

5. OTA Update Cluster Incomplete

Current implementation is a stub:

# Returns empty list and claims update not possible
return TLV.Matter_TLV_array()   # empty list for now TODO
return tlv_solo.set(TLV.BOOL, 0)  # we claim that update is not possible

LOW PRIORITY Gaps

6. Group Key Management Incomplete

Marked as TODO in the code:

elif cluster == 0x003F              # ========== Group Key Management Cluster 11.2 p.572 ==========
  # TODO

7. Diagnostic Logs Cluster Empty

No attributes implemented:

elif cluster == 0x0032              # ========== Diagnostic Logs Cluster 11.10 p.637 ==========
  # no attributes

8. Software Diagnostics Cluster Empty

elif cluster == 0x0034              # ========== Software Diagnostics Cluster 11.12 p.654 ==========
  # no mandatory attributes - to be added later (maybe)

Session/Security Analysis

PASE Implementation

✅ Compliant - Full SPAKE2+ implementation with correct CHIP context prefix.

CASE Implementation

✅ Compliant - Full Sigma1/Sigma2/Sigma3 protocol with:

• Proper certificate chain validation
• ECDH key exchange
• Session key derivation via HKDF
• Session resumption support

Known Deviations (Acceptable)

1. Context Prefix: Uses "CHIP PAKE V1 Commissioning" instead of spec's "Matter PAKE V1 Commissioning" - this is correct for interoperability
2. PBKDF2 Iterations: Uses minimum 1000 - compliant but minimal security

Recommendations

Immediate (High Value)

1. Add Energy Measurement Plugins

   • Leverage existing Tasmota energy drivers
   • Implement clusters 0x0090 and 0x0091
   • High value for smart home energy monitoring

2. Add Thermostat Plugin

   • Implement cluster 0x0201
   • Map to Tasmota thermostat commands

Short-term

3. Enable ICD Support

   • Uncomment and test ICD cluster
   • Important for battery devices

4. Add Power Source Cluster

   • Report battery/wired status
   • Important for portable devices

Long-term

5. Complete OTA Cluster

   • Enable Matter-based firmware updates

6. Add Water Heater Support (Matter 1.4)

   • New device type for water heater control

Compatibility Notes

The current implementation is fully compatible with Matter 1.0/1.1 controllers and should work with Matter 1.4 controllers for supported device types. The gaps primarily affect:

1. New Matter 1.4 device types (not supported)
2. Energy monitoring features (not exposed via Matter)
3. Advanced diagnostics (minimal implementation)

Controllers like Apple Home, Google Home, and Amazon Alexa will work with the current implementation for all supported device types.

Additional Technical Details

Commissioning Implementation

The commissioning implementation (Matter_z_Commissioning.be) is well-structured:

Fabric Management

The fabric implementation (Matter_Fabric.be) supports:

Interaction Model

The IM implementation (Matter_IM.be) supports:

Note: Opcodes marked "device mode" are for controller-side operations, not needed for a Matter device.

mDNS Service Records

Commissioning (_matterc._udp):

• VP (Vendor+Product)
• D (Discriminator)
• CM (Commissioning Mode)
• T (TCP support = 0)
• SII/SAI (Sleep intervals)
• Subtypes: _L<discriminator>, _S<short>, _V<vendor>, _CM1

Operational (_matter._tcp):

• Instance: <compressed_fabric>-<device_id>
• Subtype: _I<compressed_fabric>

Matter 1.4.1 Specific Features

Matter 1.4.1 (May 2025) added:

These features are primarily controller-side or require specific hardware support.

Implementation Quality Assessment

Strengths

1. Clean Architecture - Well-separated concerns (Session, Fabric, Commissioning, IM)
2. Optimized Paths - Fast-track processing for common operations
3. Robust Persistence - JSON-based fabric/session storage
4. Good Logging - Comprehensive debug output
5. Bridge Support - Remote device aggregation

Areas for Improvement

1. Energy Clusters - High-value gap for Tasmota's energy monitoring
2. Thermostat - Missing despite Tasmota having thermostat support
3. ICD - Code exists but disabled
4. Diagnostics - Minimal implementation

Analysis Date: January 2026 Based on Tasmota Matter Berry implementation Compared against Matter 1.4.1 Core Specification

Related Documents

• MATTER_1.4.1_DETAILED_GAP_ANALYSIS.md - Comprehensive gap analysis with implementation requirements, code examples, and roadmap
• MATTER_CLASS_HIERARCHY.md - Plugin class hierarchy documentation
• MATTER_SESSION_ARCHITECTURE.md - PASE/CASE session establishment
• MATTER_ICD_IMPLEMENTATION.md - ICD cluster implementation details