vSphere and VMware Cloud Foundation (VCF) 9.1 "Back-in-Time" Release Support
Article ID: 450972
Updated On:
Products
Issue/Introduction
When planning an upgrade, convergence, or import into VMware Cloud Foundation (VCF) 9.1, administrators may encounter unsupported path warnings related to "Back-in-Time" release restrictions.
A back-in-time condition occurs when a source software version (such as vSphere 8.0 Update 3j or VCF 5.2.4) was released after the target software build (such as VCF 9.1.0 GA). Understanding how back-in-time rules apply to VCF 9.1 workflows—and leveraging alternative onboarding paths like the Import workflow—is critical for successful fleet management and upgrade planning.
Environment
Target Release: VMware Cloud Foundation (VCF) 9.1 / vSphere 9.1
Source Releases:
vSphere 8.0 Update 3 series (e.g., 8.0U3, 8.0U3i, 8.0U3j, 8.0U3k)
VMware Cloud Foundation 5.2.x series (e.g., VCF 5.2.0–5.2.3, VCF 5.2.4)
VMware vCenter Server 8.x
VMware vSphere ESXi 8.x
Cause
A back-in-time scenario occurs when an upgrade attempt is made from a source release that contains code fixes, security patches, or driver updates that are not yet present in the target release.
Risk: Upgrading in a back-in-time scenario is unsupported because it would cause an unintended regression of security fixes, critical patches, or stability code.
Example: Upgrading from vCenter/ESXi 8.0 Update 3j (released after VCF 9.1.0) directly to VCF 9.1.0 is blocked because 8.0U3j includes patch code not yet integrated into the 9.1.0 GA release.
Interoperability Management: VMware by Broadcom manages back-in-time restrictions dynamically through the VMware Interoperability Matrix Tool (by unchecking "Hide Patch Releases").
Resolution
VCF 9.1 supports three distinct onboarding workflows to bring existing infrastructure under a VCF 9.1 Fleet. Back-in-time compatibility differs across these three workflows:
Upgrade: Moving an existing VCF deployment to a VCF 9.1 Fleet.
Converge: Converging an existing vSphere-based (non-VCF) environment into a new VCF 9.1 Fleet.
Import: Bringing an existing vSphere-based (non-VCF) environment under the management of an existing VCF 9.1 Fleet without performing an immediate software version upgrade.
| Source Version | Target Version | Upgrade | Converge | Import |
| vSphere 8.0U3 – 8.0U3i | VCF 9.1.0 | Supported | Supported | Supported |
| vSphere 8.0U3j – 8.0U3k | VCF 9.1.0 | Unsupported | Unsupported | Supported |
| VCF 5.2.0 – 5.2.3 | VCF 9.1.0 | Supported | N/A | N/A |
| VCF 5.2.4 | VCF 9.1.0 | Unsupported | N/A | N/A |
Key Workflow Considerations & Guidance
1. The Import Workflow (Workaround for Back-in-Time Versions)
If your environment runs a back-in-time version (e.g., vSphere 8.0 Update 3j/3k), you cannot perform a direct Upgrade or Converge to VCF 9.1.0 at this time. However, you can use the Import workflow:
Why it works: The Import workflow is an onboarding operation rather than an upgrade operation. It brings an existing vSphere environment under VCF 9.1 Fleet Management while leaving the underlying ESXi/vCenter builds on their current vSphere 8.0 Update 3 patches.
Fleet Management Benefits: Imported environments immediately gain central visibility, lifecycle management capabilities, and VCF Operations capabilities—including ESXi certificate and password management—without requiring an immediate upgrade to vSphere 9.1.
2. Future Patch Resolution
Support for direct Upgrade and Converge paths for back-in-time releases (e.g., vSphere 8.0U3j+ and VCF 5.2.4) is targeted for a future VCF 9.1.x patch release. Once the target VCF 9.1.x patch incorporates the code lines from those source updates, direct upgrades and conversions will be enabled.
Verification Tools & Diagnostics
To verify whether your source version is impacted by back-in-time release restrictions prior to initiating an upgrade:
vSphere Release Notes: Review the release notes for your current build. Back-in-time releases explicitly document upgrade restrictions. For example:
"Upgrade from vCenter 8.0 Update 3j to vCenter 9.1.0 or any EP based on 9.1.0 is not supported. Forward upgrade path to 9.x will be available in a future 9.x patch release."
VMware Product Interoperability Matrix:
Access the VMware Interoperability Matrix Tool.
Search for vCenter Server or vSphere ESXi compatibility with VCF.
Ensure you uncheck the "Hide Patch Releases" checkbox to display patch-level granularity.
Unsupported back-in-time paths are clearly indicated with an X icon accompanied by explanatory hover text.
Additional Information
Feedback
