Upgrading legacy replication sets to V2 in Instance Data Replication

  • Release version: Yokohama
  • Updated May 13, 2025
  • 2 minutes to read
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    Summary of Upgrading legacy replication sets to V2 in Instance Data Replication

    ServiceNow customers using Instance Data Replication (IDR) should upgrade legacy replication sets to V2 to improve message processing and replication performance. Legacy replication sets, based on an older Kafka message transport, are planned for deprecation by the Zurich release. V2 replication sets leverage the Hermes Messaging Service, a more reliable and scalable AI Platform capability, ensuring faster data replication. Upgrading is essential to maintain continuous data replication and take advantage of these enhancements.

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    Key Features

    • Legacy vs. V2 replication sets: Legacy sets use pre-Utah release Kafka transport; V2 sets use Hermes Messaging Service activated with the IDR plugin.
    • Continuous replication during upgrade: Data replication remains active throughout the upgrade process, eliminating downtime.
    • Upgrade eligibility: Both producer and consumer instances must be on Utah or later. Not all Utah legacy sets are eligible, especially if configured as bidirectional or discrete.
    • Compatibility requirements: V2 producer sets work only with V2 consumer sets. Upgrading both sides is necessary to realize V2 benefits.
    • Message retention: Data sent from V2 producer sets is retained in the message queue for 24 hours, enhancing reliability.

    Practical Guidance

    • Check upgrade eligibility for each replication set via the Upgrade Eligibility column in the Consumer Subscriptions related list.
    • Upgrade can be done by creating new V2 replication sets or upgrading existing legacy sets seamlessly without pausing replication.
    • If an upgrade fails, IDR automatically rolls back to maintain system stability.

    What You Can Expect

    By upgrading to V2 replication sets, you gain faster, more reliable, and scalable data replication across your ServiceNow instances. This upgrade ensures compatibility with future releases and leverages the AI-enabled Hermes Messaging Service for improved performance. Maintaining up-to-date replication sets is critical to prevent disruption as legacy sets become unsupported in upcoming releases.

    Improve message processing and replication performance by upgrading your legacy replication sets in IDR to V2.

    Legacy and V2 replication sets

    Important:
    Legacy replication sets are planned for deprecation by the Zurich release. To continue replicating data, you must upgrade all legacy replication sets to V2.
    • Legacy replication sets use a ServiceNow Kafka message transport and delivery implementation that was created prior to the Utah release. All replication sets created prior to the Utah release are considered legacy replication sets.

      Beginning with the Washington DC release, you can no longer create legacy replication sets.

    • V2 replication sets use the ServiceNow Hermes Messaging Service for Kafka message transport and delivery, which replicates data faster, at scale, and with high reliability. The Hermes Messaging Service is a ServiceNow AI Platform capability that's automatically enabled when the IDR plugin (com.glide.idr) is activated. All replication sets created after the Washington DC release are V2 replication sets.
    Note:
    Data sent from a V2 producer replication set is retained in the message queue for 24 hours.

    Upgrading legacy replication sets

    Upgrade your eligible legacy replication sets to V2 to take advantage of the benefits provided by Hermes. Upgrading replication sets from legacy to V2 is a seamless process. Active data replication from the producer to consumer continues throughout the upgrade, which means you don't need to pause replication before you begin. Replication continues using the V2 replication sets after the upgrade is finished.

    You can either create new V2 replication sets or upgrade existing legacy replication sets to V2. See Upgrade legacy replication sets in Instance Data Replication.

    Upgrade eligibility

    Legacy replication sets are eligible for upgrade to V2 when both the producer and consumer instance are on Utah or higher. Note that some Utah legacy replication sets aren't eligible for upgrade to V2, depending on their configuration (for example, the replication set can't be bidirectional or discrete).

    You can confirm upgrade eligibility by viewing the producer replication set and checking the Upgrade Eligibility column in the Consumer Subscriptions related list.

    • If the value for each subscribed consumer is Eligible, you can begin the upgrade process by following the steps in Upgrade legacy replication sets in Instance Data Replication.
    • If the value for a subscribed consumer is Not eligible, this means that either the consumer instance isn't on Utah or higher, or the consumer replication set is on Utah, but isn't eligible for upgrade to V2 because of its configuration.

    For details on which types of legacy replication sets are eligible for upgrade in Utah, refer to the "Upgrading legacy replication sets to V2" topic in the Utah version of the IDR documentation.

    Compatibility

    V2 producer replication sets are compatible only with V2 consumer replication sets.

    If you upgrade a producer replication set to V2, you must upgrade the subscribed consumer replication sets to V2 as well to take advantage of the V2 processing improvements.