What’s new

About this release

The technology you trust from XenServer, the high-performance hypervisor optimized for virtual app and desktop workloads and based on the Xen Project hypervisor, is now Citrix Hypervisor.

Citrix Hypervisor 8.1 is a Current Release (CR). The Current Release model allows customers to consume new features at the earliest possible juncture. A Current Release contrasts with the Long Term Service Release (XenServer 7.1 LTSR), which guarantees stability in terms of the feature set.

Citrix Hypervisor 8.1 is available in the following editions:

  • Premium Edition (previously Enterprise Edition)
  • Standard Edition
  • Express Edition (previously Free Edition)

For information about the features available in each edition, see the Citrix Hypervisor Feature Matrix.

New features and improvements in Citrix Hypervisor 8.1

Citrix Hypervisor 8.1 introduces enhanced features and functionality for application, desktop, and server virtualization use cases. All Citrix Hypervisor 8.1 features are available to all licensed Citrix Virtual Apps and Desktops (formerly XenApp and XenDesktop) customers.

Guest UEFI boot and Secure Boot

Citrix Hypervisor enables VMs running Windows 10 (64-bit), Windows Server 2016 (64-bit), or Windows Server 2019 (64-bit) to boot in UEFI mode. UEFI boot provides a richer interface for the guest operating systems to interact with the hardware, which can significantly reduce Windows VM boot times.

For these Windows operating systems, Citrix Hypervisor also supports Windows Secure Boot. Secure Boot prevents unsigned, incorrectly signed or modified binaries from being executed during boot. Secure Boot also reduces the risk that malware in the guest can manipulate the boot files or run during the boot process.

For more information, see Windows VMs


Guest UEFI boot was provided in Citrix Hypervisor 8.0 as an experimental feature. If you created UEFI boot VMs with Citrix Hypervisor 8.0 you cannot migrate them to Citrix Hypervisor 8.1. You must shutdown these UEFI boot VMs before updating to Citrix Hypervisor 8.1.

Multiple vGPU

For NVIDIA GPUs and drivers that support multiple vGPU, you can configure a single VM to use multiple virtual GPUs concurrently. These additional vGPUs can be used to perform computational processing. Only certain vGPU profiles can be used and all vGPUs attached to a single VM must be of the same type.

For more information, see Graphics Overview.

Performance improvements

Improved performance for VM imports and exports that use the XVA format

Changes to the checksum used in XVA files in Citrix Hypervisor 8.1 provide significant performance improvements when importing or exporting VMs using this new checksum algorithm.

The reduction in the time it takes to import or export a VM depends on the specific hardware of the machine. The larger the VM the larger the performance improvement seen.

Use XenCenter 8.1 to manage exported VMs that use XVA files with the new checksum algorithm.

If you have a custom application that relies on the format of the checksum included in the XVA file, update your application to use the new format. The checksum has changed to use the xxHash algorithm. The checksum file name now ends with the extension .xxhash.

Storage performance improvements

Citrix Hypervisor 8.1 includes the following performance enhancements to storage:

  • Storage performance is significantly improved when I/O is performed in block sizes larger than 64 KiB on an NFS SR.

  • Multipage support is now available in non-GFS2 SRs for better storage performance. If your Windows VM has the Citrix VM Tools installed, the VM uses multipage support automatically. To enable multipage support on a Linux VM complete the following steps:

    1. First, verify that your kernel supports the max_ring_page_order parameter. Run the following command:

      modinfo xen_blkfront | grep max_ring_page_order

      If this command returns an empty response, your kernel does not support this feature. Do not proceed with these steps.

    2. Take a snapshot of your VM.

    3. On the VM, run the following command:

      echo 'options xen_blkfront max_ring_page_order=3' >/etc/modprobe.d/xen_blkfront.conf
    4. Depending on your Linux distribution, run one of the following commands:

      • For RHEL, CentOS, or Oracle Enterprise Linux: dracut -f -v
      • For Debian-based distributions: update-initramfs -u -k all
    5. Reboot your VM.

New Windows I/O drivers with improved performance

Updated Windows I/O drivers with the major version 9 (9.x.x.x) are provided with this release of Citrix Hypervisor for the following operating systems: Windows 8.1, Windows 10, Windows Server 2012, Windows Server 2012 R2, Windows Server 2016, Windows Server Core 2016, Windows Server 2019, Windows Server Core 2019. These Windows I/O drivers include a number of performance improvements.

These drivers are also available through Windows Update for Premium Edition customers.

Windows I/O drivers with the major version 8 (8.x.x.x) are still provided for the older supported Windows operating systems. These drivers do not contain the performance improvements.

Changes to guest operating system support

The set of guest operating systems that Citrix Hypervisor supports has been updated. For more information, see Guest operating system support


Citrix Hypervisor now supports the following additional guest operating systems:

  • SUSE Linux Enterprise Server 12 SP4 (64-bit)
  • SUSE Linux Enterprise Desktop 12 SP4 (64-bit)
  • SUSE Linux Enterprise Server 15 SP1 (64-bit)
  • SUSE Linux Enterprise Desktop 15 SP1 (64-bit)
  • Red Hat Enterprise Linux 8 (64-bit)
  • Oracle Enterprise Linux 8 (64-bit)
  • CentOS 8 (64-bit)
  • Debian Buster 10 (64-bit)


The following guest operating system requirements changed in Citrix Hypervisor 8.1:

  • Windows 10

    In previous releases of Citrix Hypervisor, the minimum disk space supported for Windows 10 was 24 GB. It is now 32 GB for new Windows 10 VMs. For more information, see What’s new in Windows 10, version 1903.


Support for paravirtualized (PV) VMs has been removed in this release of Citrix Hypervisor. XenCenter warns you during update or upgrade that PV guests are no longer supported.

You can import existing VMs that use these operating systems into your Citrix Hypervisor 8.1 installation. However, Citrix does not provide support for VMs with these operating systems. Upgrade your VMs to a more recent and supported version of the OS as soon as possible. For more information, see Upgrade from PV to HVM guests.

Support for the following guest operating systems has been removed:

  • Ubuntu 14.04
  • Red Hat Enterprise Linux 5
  • Red Hat Enterprise Linux 6
  • CentOS 5
  • CentOS 6
  • Oracle Enterprise Linux 5
  • Oracle Enterprise Linux 6
  • Scientific Linux 6
  • NeoKylin Linux Advanced Server 6.2
  • Debian Wheezy 7
  • SUSE Linux Enterprise Server 11 SP3
  • SUSE Linux Enterprise Server 11 SP4
  • SUSE Linux Enterprise Server 12
  • SUSE Linux Enterprise Server 12 SP1
  • SUSE Linux Enterprise Server 12 SP2
  • SUSE Linux Enterprise Desktop 11 SP3
  • SUSE Linux Enterprise Desktop 12
  • SUSE Linux Enterprise Desktop 12 SP1
  • SUSE Linux Enterprise Desktop 12 SP2

Changes to processor support

The following processors are now supported in Citrix Hypervisor 8.1:

  • AMD EPYC 7xx2(P)

For more information, see the Hardware Compatibility List.

Citrix Hypervisor Conversion Manager console capabilities are now included in XenCenter

In Citrix Hypervisor 8.0 and earlier, a separate Conversion Manager console was provided. From Citrix Hypervisor 8.1, this capability is integrated into XenCenter. The legacy Citrix Hypervisor Conversion Manager console has been retired.

The conversion plugin that was previously included in the Citrix Hypervisor server installation has also been removed from Citrix Hypervisor 8.1. The removal of this plugin means that you must use the latest version of XenCenter, which includes the conversion capability, with Citrix Hypervisor 8.1. (You cannot use older versions of the Conversion Manager console with Citrix Hypervisor 8.1.)

However, the Conversion Manager virtual appliance is still required for converting VMware VMs to Citrix Hypervisor VMs. This component is provided on the Citrix Hypervisor Product Download page.

For more information, see Convert VMware workloads.

XenCenter alerts for end of life or end of support

XenCenter now alerts you when the version of your managed Citrix Hypervisor servers is approaching end of life or reaches end of life. For more information, see XenCenter Alerts.

XenCenter also alerts you when a Current Release or Cumulative Update is approaching or has passed a date when there will be no further hotfixes issued for that release. Act upon this information and update your environment to a later supported release, to ensure that updates to address any future functional and security related issues can be applied.

Installation options

Citrix Hypervisor 8.1 is available to download from the Citrix Hypervisor Product Download page in the following packages:

  • Citrix Hypervisor 8.1 Update ISO. Use this file to apply Citrix Hypervisor 8.1 as an update to Citrix Hypervisor 8.0.

  • Citrix Hypervisor 8.1 Base Installation ISO. Use this file to create a fresh installation of Citrix Hypervisor 8.1 or to upgrade from XenServer 7.6, 7.1 Cumulative Update 2, or 7.0.


  • If you use XenCenter to upgrade your hosts, update your XenCenter installation to the latest version supplied on the Citrix Hypervisor 8.1 download page before beginning.
  • Always upgrade the pool master before upgrading any other hosts in a pool.
  • Ensure that you update your XenServer 7.1 to Cumulative Update 2 before attempting to upgrade to Citrix Hypervisor 8.1.

Before you start

Before beginning installation or migrating from an older version, review the following articles:

For information about the installation, upgrade, or update process, see Install

Changing from the Long Term Service Release to the Current Release

If you’re running a XenServer LTSR, but want to take advantage of new features, you can decide to change to the Citrix Hypervisor CR stream. Using the Citrix Hypervisor versions from the CR stream requires you to adopt new CRs regularly to remain in support.

Move to this Current Release by upgrading from XenServer 7.1 Cumulative Update 2 LTSR.

Changing from the Current Release to the Long Term Service Release

If you’re running a Citrix Hypervisor CR, but instead want to move to a version of Citrix Hypervisor with a guaranteed and fixed feature set, you can change to a XenServer LTSR. The latest XenServer LTSR is available to download from the Citrix Hypervisor Product Download page.

Move to the latest LTSR by creating a fresh installation of XenServer 7.1 Cumulative Update 2 LTSR.

For more information about LTSRs and CRs, see Citrix Virtual Apps, Citrix Virtual Desktops, and Citrix Hypervisor Servicing Options.


Customers must upgrade their Citrix License Server to version 11.14 or higher to use all Citrix Hypervisor 8.1 licensed features.

For more information about Citrix Hypervisor 8.1 licensing, see Licensing.

Hardware compatibility

For the most recent additions and advice for all hardware compatibility questions, see the Citrix Hypervisor Hardware Compatibility List.

If you have VMs with attached virtual GPUs, ensure that supported drivers are available before upgrading to the latest release of Citrix Hypervisor. For more information, see both the Hardware Compatibility List and the GPU vendor documentation.

Interoperability with Citrix products

Citrix Hypervisor 8.1 is interoperable with Citrix Virtual Apps and Desktops 7 1912.

Citrix Hypervisor 8.1 is interoperable with Citrix Provisioning 1912.

Citrix Hypervisor 8.1 is interoperable with Citrix Cloud.

For more information about interoperability with other Citrix products, see the Citrix Upgrade Guide.

Localization support

The localized version of XenCenter (Simplified Chinese and Japanese) is also available in this release.

Product documentation

To access Citrix Hypervisor 8.1 product documentation, see Citrix Hypervisor 8.1 Product Documentation.

Documentation can be updated or changed after the initial release. We suggest that you subscribe to the Document History RSS feed to learn about updates.