The transition from VMware Horizon to Omnissa Horizon introduced more than just a branding change. Starting with Horizon 2412 and continuing with later releases such as 2503 and 2506, several architectural and configuration elements have been modified.

These changes include licensing format updates, ADAM/AD LDS database modifications, registry key renaming, folder restructuring, and updated group policy templates.

While the official upgrade path works, in many environments a parallel deployment strategy can significantly reduce risk and allow end users to validate the new platform before switching production workloads.

This article outlines the key changes introduced by Omnissa and explains why building a new Horizon pod alongside the existing one can be a practical migration strategy.

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Key Changes Introduced with Omnissa Horizon

1. New Licensing Model

Beginning with Horizon 2412, Omnissa introduced a new licensing mechanism and licensing portal.

During the transition phase, both VMware and Omnissa license keys are temporarily accepted, but this compatibility window is limited. Later releases, such as 2503.1 ESB and 250,6 rely entirely on the Omnissa License Module (OLM).

If a valid Omnissa license key is not installed after upgrading, the Horizon Console may enter a restricted or degraded mode.

Relevant KB and documentation references include:

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2. ADAM / AD LDS Database Changes

One of the most important backend changes affects the Horizon LDAP (ADAM/AD LDS) database.

Historically, Horizon used application partitions referencing the VMware namespace.
With the Omnissa rebranding, new environments now use the horizon namespace.

Example:

Old partition naming:

dc=vdi,dc=vmware,dc=int

dc=vdiglobal,dc=vmware,dc=int

New partition naming:

dc=vdi,dc=horizon,dc=internal

dc=vdiglobal,dc=horizon,dc=internal

Omnissa provides a migration script to update the partition names after upgrading all pods to newer versions, such as 2503.

Relevant documentation:

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3. Registry Key and File System Changes

The rebranding also impacted multiple components of the Horizon installation:

Because registry paths changed, Group Policy templates (ADMX) were also updated and must be replaced during upgrades.

Failure to update the ADMX files can lead to policies silently no longer applying.

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Why a Parallel Horizon Deployment Can Be a Better Migration Strategy

Although a direct upgrade of the Connection Servers is supported, the number of changes introduced with the Omnissa transition makes a greenfield-style deployment attractive.

Instead of upgrading the existing servers, consider deploying new Connection Servers alongside the current environment.

Advantages include:

1. Opportunity to Upgrade Windows Server

New Connection Servers allow administrators to deploy a modern operating system, such as:

This avoids performing multiple upgrades on the same system.

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2. User Acceptance Testing

With a parallel deployment, you can:

Users can test the environment before the production switch.

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3. Reduced Upgrade Risk

Upgrading in place modifies:

A clean installation avoids potential issues caused by legacy configurations.

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Example Parallel Migration Architecture

A typical migration architecture might look like this:

Existing Environment

New Environment

*After migration, it will be upgraded.

This allows a staged migration.

Key points:

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Migrating Instant Clone Desktop Pools

In environments heavily using Instant Clones, rebuilding pools manually can be time-consuming.

Automation scripts can accelerate the process by exporting and recreating pools through the Horizon APIs.

In my environment, I use a PowerShell-based migration script that reads the configuration of Instant Clone pools and recreates them on the new pod.

This allows administrators to migrate:

with minimal manual effort.

This is the link to the script

OMNISSA/OMNISSA – Export and Import Desktop and Entitlements v7.ps1 at main · fabio1975/OMNISSA

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Reusing DEM and App Volumes

Existing deployments of

can usually remain unchanged during migration.

However, compatibility must always be validated using the official interoperability matrix.

Relevant documentation:

Official documentation:

These matrices confirm supported combinations between:

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Suggested Migration Workflow

A practical migration process could look like this:

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Final Thoughts

The transition from VMware Horizon to Omnissa Horizon introduces several structural changes that go beyond simple branding.

Changes in licensing, LDAP partitions, registry paths, and policy templates can complicate traditional upgrade workflows.

For many environments, especially large VDI deployments, deploying new Connection Servers in parallel offers a safer and more flexible migration strategy.

It provides an opportunity to modernize the infrastructure, validate compatibility with components such as App Volumes and DEM, and allow users to test the platform before the final cutover.

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