Deyda.net – Deyda Consulting Blog

Citrix License Activation Service (LAS): Goodbye License Files

If you’re a Citrix customer and thinking “next week…” right now — understandable. But starting April 15, 2026, file-based Citrix license files will no longer work. This is not a warning; it’s a hard shutdown date.

That means: if you haven’t migrated to LAS by then, you risk real outages (apps, desktops, or features depending on the component and version).

LAS is not a migration of your workloads to the cloud. Your site continues to run on-premises (DDCs, StoreFront, VDAs, etc.).
The only thing that changes is the activation and licensing mechanism.

Workaround after Remote Assistance Error

After installing the January 2026 Microsoft security updates, Remote Assistance (msra.exe) no longer works on multiple Windows versions. This directly affects Citrix Director Shadowing, as the generated invite files can no longer be opened on patched systems.

The issue is caused by a security hardening related to CVE-2026-20824 – Windows Remote Assistance Security Feature Bypass Vulnerability. While the fix is technically correct from a security perspective, it currently breaks legitimate Remote Assistance workflows in enterprise environments.

Migration of Citrix databases

With the latest Citrix Virtual Apps & Desktops (CVAD) LTSR version, older SQL Server versions have been discontinued. If you want to keep your environment stable and supportable, there is no way around migrating the Citrix databases (site, logging, monitoring) to modern SQL servers (2019/2022). Whether cluster, always on or mirroring – the procedure remains essentially the same. In this article, I will show you step by step how to migrate securely.

1. Prerequisites

Complete backups of all Citrix databases
Backups/VM snapshots of the delivery controllers (DDCs)
New SQL Server (Cluster, Always On or Mirror)
Same SQL version on Principal and Mirror

Checklist for NetScaler (Citrix ADC) CVE-2025-5777 & CVE-2025-6543

On June 17, 2025, Citrix published a security advisory for CVE-2025-5777, followed by CVE-2025-6543 on June 25, 2025. Both are classified as critical and are actively being exploited in the wild.

Threat Overview

CVE-2025-5777: Critical vulnerability due to improper input validation → leads to memory overread
CVE-2025-6543: Enables memory overflow, potentially resulting in DoS or arbitrary code execution → Exploits available !

⚠️ Important: Simply applying the firmware update is not enough. You must manually terminate all active ICA and PCoIP sessions after patching to ensure the vulnerability is fully mitigated.

Install new Microsoft Teams (version 2) in Citrix

The New Teams version (sometimes also called Teams 2.0) will become the new standard for Microsoft’s communication platform from July 1, 2024. On October 1, 2024, the Classical Teams client in the VDI context will reach its end of support and, according to the latest news, its end of availability date on July 1, 2025. These end dates have been adjusted several times in recent weeks.