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MQTT 5: Seven Reasons to Upgrade to it from MQTT 3.1.1 – MQTT 5 Essentials Part 3

by Ian Skerrett, Florian Raschbichler
14 min read

The Internet of Things (IoT) has evolved rapidly over the last decade, with MQTT emerging as the de facto protocol for the seamless and efficient communication of IoT devices. As the scale and complexity of IoT systems grow, the MQTT protocol is also evolving to meet these demands. In this light, the MQTT 5 upgrade presents significant improvements catering to modern IoT applications’ expanding needs.

In Part 2 of this MQTT 5 Essential series, MQTT 5 Vs. MQTT 3, we delved deep into the changes introduced in MQTT 5. In this article, we will explore why your organization or development team should consider upgrading to MQTT 5 from MQTT 3.1.1.

Why Upgrade to MQTT 5 from MQTT 3?

MQTT 5 represents a substantial enhancement to the MQTT protocol, developed with valuable insights from MQTT users. It incorporates features essential for contemporary IoT applications, tailor-made for cloud-based deployments. These advancements promote resilience, dependable error management for executing crucial messaging, and facilitate the straightforward integration of MQTT messages into existing computational frameworks.

In this article, we present seven reasons why your organization or development team should consider upgrading to MQTT 5; they include:

  1. Better Error Handling for More Robust Systems

  2. More Scalability for Cloud Native Computing

  3. Greater Flexibility and Easier Integration

  4. The Rise of a Single IoT Standard

  5. Future-Proofing

  6. Streamlined Migration

  7. Improved features, including:

    1. Negative Acknowledgments

    2. Topic Aliases for Efficiency

    3. User Properties for Customization

    4. Payload Format Indicators

Here is the rationale behind how and why MQTT 5 is better compared to MQTT 3.

1. How MQTT 5 is Better Than MQTT 3 in Error Handling

MQTT 5 significantly enhances error-handling mechanisms, contributing to the robustness and reliability of the system. One of the notable introductions is the session and message expiry feature. This allows developers to set a defined time limit for each message and session. If a message isn’t delivered within this time frame, it’s automatically deleted. This feature is particularly useful in ensuring that network latency or outages do not lead to delivering outdated or irrelevant commands to IoT devices.

2. How MQTT 5 is Better Than MQTT 3 in Offering Greater Scalability

Scalability is a crucial requirement in the modern world of growing IoT networks. MQTT 5 addresses this by standardizing shared subscriptions. This allows multiple MQTT client instances to share the same subscription on the broker. It’s a powerful feature for load-balancing MQTT clients deployed on a cloud cluster. This scalability makes MQTT 5 a robust choice for enterprises with large deployments and those planning to scale up their IoT systems.

3. How MQTT 5 is Better Than MQTT 3 in Offering Greater Flexibility and Easier Integration

Taking customization to a new level, MQTT 5 introduces User Properties, a feature that allows for adding key-value properties to the headers of MQTT messages. This capacity means that application-specific information can be incorporated directly into each message, enhancing the processing of these messages. For instance, a meta-tag that includes the unique identifier of the sending client or the firmware version of the device platform can be added to the message header, facilitating analysis and processing by the receiver.

Additionally, MQTT 5 simplifies the process for the receiver by incorporating Payload Format Indicators. Now it’s easier to differentiate between binary or text data, as MQTT 5 includes a MIME-style content type descriptor. This feature provides immense value across a plethora of use cases. Consider, for example, a toll road control system transmitting images of license plates for image recognition processing. In contrast, other messages might require a different processing style, like those including location coordinates. By specifying the format, MQTT 5 ensures efficient and appropriate processing of diverse data types.

4. How MQTT 5 is Better Than MQTT 3 as an IoT Standard

With its rich feature set, MQTT 5 has cemented its place as the go-to choice for diverse IoT use cases, successfully addressing the limitations of previous versions. We anticipate exponential MQTT adoption across industries in the coming years, hinting at MQTT’s impending status as the universal IoT standard.

5. How MQTT 5 is Better Than MQTT 3 in Future-Proofing Your Applications

By addressing the limitations of MQTT 3, MQTT 5 paves the way for future enhancements in IoT applications. Its flexible and robust features make it adaptable to upcoming technology trends, ensuring your IoT systems stay current and ready for future advancements.

6. How MQTT 5 is Compatible With its Predecessors

One of the practical advantages of MQTT 5 is its compatibility with its predecessors. It supports MQTT 3.1 and MQTT 3.1.1 features, allowing a mix of MQTT 3 and MQTT 5 clients. This makes the migration process seamless, enabling organizations to gradually transition to MQTT 5 without disrupting existing IoT operations.

7. How is MQTT 5 Better Than MQTT 3 in Offering Improved Features

In this section, we delve into an array of MQTT5’s enhanced features. From bolstering system robustness with Negative Acknowledgments to enabling customization with User Properties and boosting efficiency with Topic Aliases, MQTT 5 has significantly emphasized usability, flexibility, and performance. Moreover, Payload Format Indicators have been introduced to facilitate easy handling of diverse data types. Let’s explore each of these advancements in detail:

Negative Acknowledgments

In a further bid to bolster system robustness, MQTT 5 incorporates the concept of negative acknowledgments. The broker can reject specific messages under predefined conditions or restrictions, such as exceeding the maximum message size, maximum quality of service (QoS), or using unsupported features. This proactive measure guards against MQTT clients that might start sending erroneous or malicious messages, significantly enhancing the overall system’s security.

Topic Aliases for Efficiency

In large systems with complex topic structures, topic strings can become long, increasing network and processing load. MQTT 5 introduces topic aliases, which lets you replace these long topic strings with integer values. This can considerably reduce the demand on the network and the processing overhead, thereby boosting system efficiency and performance.

User Properties for Customization

MQTT 5 goes a step further in customization by introducing User Properties. These allow developers to add key-value properties to the message header of an MQTT message. This level of customization enables you to include application-specific information within each message. This data could be used to enrich message processing and integration, giving developers more flexibility and control over their applications.

Payload Format Indicators

With the diverse types of data in IoT applications, it’s crucial to have a mechanism that simplifies data handling and processing. MQTT 5 meets this need with payload format indicators. These indicators identify whether the payload is binary or text and include a MIME-style content type. This helps improve data processing efficiency and makes the system more adaptable to various data use cases.

Conclusion: MQTT 5 - The Game Changer in IoT Communications

MQTT 5 represents a substantial stride forward in IoT communications. It’s not simply a minor upgrade; it’s a transformation adeptly addresses previous shortcomings packed with robust features. It is an indispensable tool for modern IoT applications. MQTT 5 is more than just a good option; it’s a compelling choice for your IoT applications, ready to propel you into the future of IoT.

Learn More About MQTT 5

As we proceed with our informative series on MQTT 5, we encourage you to read the next article in this series, where we spotlight Session & Message Expiry Intervals of MQTT 5. We’ll discuss their significance in maintaining client session states and ensuring timely message delivery. This deep dive will offer insights into the practical applications of these features and their role in boosting the reliability and efficiency of IoT systems. Stay tuned for a concise yet comprehensive exploration of these key MQTT 5 functionalities.

HiveMQ: Pioneering MQTT 5 Adoption with a Comprehensive Solution


HiveMQ’s involvement with MQTT 5 extends beyond mere compatibility. A leading participant in the MQTT 5 standardization process, HiveMQ has pioneered in implementing one of the first comprehensive MQTT 5-compliant solutions. With HiveMQ, the leap to the future is seamless. This version is designed to concurrently support MQTT 5 and its predecessors, MQTT 3.1 and 3.1.1, allowing for a smooth and phased migration to MQTT 5. HiveMQ’s customers can use this versatility to deploy a blend of MQTT 3 and MQTT 5 clients, ensuring uninterrupted operations during the transition. Experience the richness of MQTT 5’s advanced features with HiveMQ and take your existing IoT deployments to new heights.

Evaluate HiveMQ Free

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FAQs on Why Upgrade to MQTT 5 from MQTT 3

Ian Skerrett

Ian is a growth-oriented marketing leader focused on B2B infrastructure, IoT, and IIoT software with over 25 years experience in the software industry. He spent 13 years with the Eclipse Foundation and was Vice President of Marketing for HiveMQ until September 2022.

  • Ian Skerrett on LinkedIn

Florian Raschbichler

Florian serves as the head of the HiveMQ support team with years of first hand experience overcoming challenges in achieving reliable, scalable, and secure IoT messaging for enterprise customers.

  • Contact Florian Raschbichler via e-mail

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