Upgrading Event Broker Services in PubSub+ Cloud

Upgrading to newer event broker service releases allows you to adopt new features and to modernize your event broker services.

Solace makes maintenance releases available for event broker services with Long Term Support (LTS) release versions during their two year support phase. Additionally, you can upgrade from any release, including a Rolling release, to any higher version release that was released after the date of your current version, and while your current version is still within its active support period.

LTS releases receive maintenance release to address product and vulnerability issues. Solace recommends upgrading to maintenance releases as they become available. You must upgrade from an LTS release to a new LTS or Rolling release before its support period ends.

Rolling releases do not receive maintenance releases. If you are using a Rolling release, you must upgrade to a higher version release, released after your currently installed version to:

  • protect the platform against new security threats
  • address critical issues
  • use more recent event broker service versions when the full support period expires

You can upgrade your event broker services at any time. Upgrading your event broker service version is not the same as upscaling your event broker service to increase its service class.

Solace has a simple procedure for upgrading event broker services, and our version adoption policy explains which event broker service version you can move to.

The following answers to common questions provide more information about upgrading:

Why Do I Need to Upgrade?

You should upgrade your event broker services for these reasons:

  • The full support phase has ended—Full support for your event broker service version is no longer available. You must upgrade to a version that is higher and released later than your currently installed version. For an example of viable upgrade paths, see Can I upgrade from an LTS release to a Rolling release, or vice versa?
  • New features or capabilities—You want to access new features or capabilities. In this situation, you can upgrade to a Rolling release that supports your upgrade path (higher version and later release date than your installed version) to receive the newest features or capabilities.
  • Security or product fixes are required—You require security or other critical updates for the current version that you're using. For LTS versions in full support, you can upgrade to a maintenance release. For Rolling releases, you must upgrade to a release that is higher and released after your currently installed version.

When Can I Upgrade?

Solace sends you product notification emails that announce LTS, Rolling, and maintenance releases in PubSub+ Cloud when they are available. You can view the planned release dates at Supported Dates for Release Versions.

You can upgrade to any version that is both:

  • a higher version than your currently installed version

  • released after your currently installed version

You can also upgrade existing LTS event broker service versions to a maintenance release. These releases are where vulnerabilities are addressed are addressed within a timeframe outlined in our version adoption policy. Solace provides these maintenance releases for LTS versions that are in full support.

How Do I Upgrade?

You can book an upgrade slot directly using Calendly. At any time, you can schedule an upgrade for any existing event broker services to the any supported release that is a higher version, in full support, and released after your currently installed version.

  • We every effort to minimize delay, but early scheduling is best to secure the time that you want. The owners of the event broker services receive notifications when an upgrade is scheduled, when the upgrade starts, and when the upgrade completes.
  • For Public Region and Dedicated Regions deployments, you don't need to be present on any calls while the upgrade occurs because Solace does the upgrade for you.

  • For deployments on Customer-Controlled Regions, a person from your organization must be available on a call to access your deployment during the short upgrade period for the event broker service.

    In Customer-Controlled Regions, the Mission Control Agent is usually upgraded automatically as part of event broker service upgrades. If your deployment includes a private repository, we recommend that you implement automation to pull the most recent images for the Mission Control Agent to ensure it is kept current. Contact Solace for more information.

What Is the Impact to My Event Broker Services When I Upgrade?

Typically, upgrading an event broker service takes only 15-30 minutes, depending on factors such as the deployment type and region. Multiple event broker services can be upgraded at the same time.

  • High-Availability—Upgrades to high-availability (HA) event broker services are in-service upgrades and do not impact client applications. A brief interruption of less than one minute occurs during the HA activity failover.
  • Developer and Standalone services—Upgrades are service affecting. During an upgrade, client applications experience an outage of 15-30 minutes because there is only one software event broker.

Upgrade durations may vary depending on factors such as the cloud provider, the region type, and the deployment options chosen.

More FAQs About the Upgrade Process

The following frequently asked questions provide answers about the upgrade process:

Can more than one event broker service be upgraded at the same time?

Yes. In a standard two-hour upgrade slot, Solace can upgrade five to six event broker services.

What happens if the upgrade fails?

We troubleshoot any errors during the upgrade slot. Errors are resolved during the remaining time in the upgrade slot when possible. If the errors can't be resolved, we open an investigation to identify the cause and provide resolution, and the event broker service is reverted to the same version before the upgrade started using our rollback procedure.

What type of validation is performed to ensure the upgrade was successful?

A standard post-upgrade checklist is followed for each upgrade to verify the event broker service metrics through our monitoring system. Validity checks determine that the service is running with the correct version. Solace recommends that you validate your client connections following the upgrade.

Will connected applications go offline during the upgrade?

During the failover period for event broker services with high-availability, there may be a temporary loss of connectivity for client applications as client applications reconnect. You do not need to disconnect them prior to the upgrade. For failover period impacts, see What Is the Impact to My Event Broker Services When I Upgrade?

Can we upgrade our environments separately?

Yes! Many of our customers take a phased approach to upgrade their event broker services starting with the least critical environments. For example, many customers start an upgrade with a development environment, and progress to staging, and then production environments. If you require a phased approach, you must book one upgrade slot per environment.

Can I initiate the upgrades myself?
Yes. At any time, schedule an upgrade via Calendly for any existing event broker services that support upgrade and are in the full support phase.
Can I upgrade from an LTS release to a Rolling release, or vice versa?
Yes. You can upgrade from an LTS release to a Rolling release, or from a Rolling release to an LTS release. When upgrading, you must upgrade to a release that is both a higher version than and that was released at a later date than your currently installed version. For example, consider the following two scenarios:
  • You can upgrade from LTS 10.25.0 to Rolling Release 10.25.6. But you cannot upgrade from 10.26.0 to 10.25.20 because it is a lower version, even though it was released later.
  • You also cannot upgrade from an older version to a newer version released before a maintenance release you are currently using. For example, you cannot upgrade from version 10.25.0.300 that released on October 2026 to 10.26.0.0 released on June 2026—you must upgrade to a version of 10.26.0 with a maintenance release after October 2026.
Does Solace retain any configuration backups or data before performing the upgrade?

No, we don't take any configuration backups before upgrades because configuration data is replicated and available for rollback when high-availability or optional disaster recovery is available. In general, there are no configuration changes performed during upgrades. You (the customer) are responsible for configuration management and backups. For more information, see Backing up Event Broker Services.

What communication method is used for upgrades?

Depending on the stage of the upgrade cycle, you can expect the following communication:

  • When your services have passed full support, you will receive an email from Solace (from [email protected]) requesting that you schedule an upgrade.
  • After you have scheduled your upgrade slot in Calendly, we create an RT service ticket in your queue to communicate any updates related to the upgrade.
  • Automated reminder emails are sent from Calendly to you in the days and hours leading up to your scheduled upgrade slot.

How are High-Availability Event Broker Services Upgraded?

Upgrades of high-availability event broker services use the following three general procedures:

  • Pre-upgrade checks—Gathers information and prepares your event broker service for the upgrade.

  • High-availability event broker service upgrade—Upgrades the event broker service.

  • Post-upgrade check—Validation to ensure that your event broker services are upgraded and running.

Pre-upgrade checks
Prior to upgrading your event broker service, Solace performs a series of pre-checks. These pre-checks ensure we have all the information required to make sure your upgrade goes smoothly in the least amount of time. We perform checks for the following information:
  • Review of your Mission Control Agent to determine if it requires any new configuration changes due to the introduction of new event broker service features. You miht need to upgrade the Mission Control Agent in Customer-Controlled Regions.
  • Identification of any special configuration that needs to be considered during the upgrade. Special configurations include (but are not limited to) items such as custom TLS certificates, the need to retain your MQTT cache, or manually provisioned Load Balancers.
  • The deployment type (Customer-Controlled Region, Public Region, or Dedicated Region) and whether we have access to your datacenter/region.
  • Whether your deployment uses any Controlled Availability features. If it does, you might need to increase the available memory footprint before the upgrade in Customer-Controlled Regions.
  • Whether any of the tags or metadata that are used by your event broker services require updates.
  • Confirmation that the event broker service images are available.

If the pre-upgrade checks fail and the upgrade cannot be performed, you will be contacted by Solace with information about why the pre-check failed, actions you can take to address the failures, and to reschedule the upgrade.

High Availability Event Broker Service Upgrade
Prior to the upgrade, the Mission Control Agent runs a series of automated checks. These checks include:
  • Redundancy
  • Config-Sync
  • DMR
  • Image Accessibility
  • MQTT Retain Memory
After the upgrade completes, the Mission Control Agent begins upgrading the event broker service over a series of steps. The Mission Control Agent pauses between each step to check that each event broker service node maintains redundancy during the process. The upgrade process begins with the primary and monitoring event brokers active, and the backup event broker in standby. From there, the individual event brokers are upgraded in the following steps:
  1. The Mission Control Agent upgrades the monitoring event broker.
  2. The Mission Control Agent upgrades the standby event broker.
  3. The Mission Control Agent ceases activity in the active event broker and transfers activity to the now upgraded standby event broker. The Mission Control Agent waits during this process to ensure the activity transfer is complete before proceeding.
  4. Once the activity transfer is complete, the Mission Control Agent upgrades the primary event broker. Once upgraded, the formerly active event broker now becomes the standby event broker.
Post upgrade checks
Once the upgrade is complete, Solace performs several post-upgrade checks to ensure your event broker service is up and running. These checks include:
  • Ensuring that the monitoring pod is up and running, that its version is correct, and that it has a connection.
  • Validating that our operational monitoring capabilities, including ensuring the upgraded service is reported as such, and that we are receiving metrics.

How Often Do I Need to Upgrade?

For the best upgrade experience, follow these recommendations:

Upgrade event broker services to the latest LTS release before support for your current version expires

You must upgrade your event broker services to a major version at least once every two years, before the support period for the version you are using ends. Full support ends two years after the software event broker version is first released. Upgrading also ensures that your event broker services are kept up-to-date with the latest security fixes. Schedule an upgrade slot with us using Calendly.

Note that Solace upgrades any event broker services that are out of the support phase to maintain the security and integrity of PubSub+ Cloud. We will attempt to contact you prior to performing the upgrade.

Upgrade regularly to get security and critical fixes

You can upgrade existing event broker service LTS versions to maintenance releases. Maintenance releases address critical and high-level vulnerabilities.See our timeline for making security fixes available in our version adoption policy. Maintenance releases are only available to LTS versions in their support phase:

  • For supported LTS versions, you can upgrade within the LTS version to a maintenance load.

    For example, if version 10.25.0 is in support, you can upgrade to 10.25.0.450 to get a fix—even if the next LTS release is available. Conversely, if 10.25.0 is out of support, you must upgrade to a later version, released after your current version of 10.25.0 to pick up the fixes.

  • PubSub+ Cloud creates new LTS event broker services with the most recent maintenance load of the version selected.

    For example, suppose you initially created an event broker service using version 10.25, which at the time was based on software event broker version 10.25.0.12. If a software event broker maintenance load with a version of 10.25.0.320 was released, all subsequent event broker services that you create with version 10.25 would use the 10.25.0.320 maintenance load of the software event broker.

Proactively schedule upgrades for your event broker services

As a customer, you are responsible for scheduling an upgrade using Calendly. Upgrades can be scheduled with at least seven calendar days' notice to allow our team adequate time to prepare for your upgrade. We make the best effort to minimize the delay for critical maintenance loads.

For more information about roles and responsibilities for upgrading, see Upgrades to Mission Control Agent and Event Broker Services.

What Happens if I Don’t Upgrade in Time?

When the support phase ends, you must upgrade. If you don't upgrade, Solace automatically proceed with upgrading your event broker services to minimize your security risk exposure and to ensure that PubSub+ Cloud remains modernized against any security and vulnerability threats.

Solace notifies you of the time and date of the upgrade slot. For Customer-Controlled Regions, Solace request that you (or a representative with access to your private region) be present during the upgrade slot. If you are not available during the upgrade slot, there is a risk that any issues that arise cannot be resolved because Solace does not have access to certain parts of your private region (private network or virtual private cloud).

Can I Downgrade an Event Broker Service?

No. Downgrading event broker services is not supported.