Site Recovery support for Debian 12 - 6.1.0-39-amd64

Hello Nick Thank you for posting your query on Microsoft Q&A platform.

• Debian 12 is supported only in the modernized experience for Azure Site Recovery. The classic experience does not support Debian 12 at all. If you are using the classic experience, migration to the modernized experience is required.
• The official Azure Site Recovery support matrix lists kernels up to 6.1.0-28-amd64 and some 6.5.x variants.
• Kernel 6.1.0-39-amd64 is not currently supported.
• Microsoft adds new kernel support through update rollups for the Mobility Service.
• There is no published ETA for 6.1.0-39-amd64 support as of now.
• New kernel support appears in incremental releases (e.g., 9.65.x), but these updates lag behind upstream Debian patches.

As a Workaround:

• Downgrade to a supported kernel (e.g., 6.1.0-28-amd64) – This is the only fully supported option today.
• Monitor update rollups – Keep checking the official support matrix for updates.
• Avoid unsupported hacks like custom module rebuilds in production; these are not endorsed by Microsoft and may break replication.
• Using an unsupported kernel can cause replication failures and prevent disaster recovery operations. Downgrading ensures stability until official support is added.

Currently, there is no official workaround that avoids downgrading the kernel. The safest approach is:

1. Switch to modernized experience if not already using it.
2. Downgrade to a supported kernel.
3. Monitor Microsoft’s update rollups for future support.

Thanks,

Suchitra.

Suchitra, thank you for the assist. I did some additional digging and found a git repo for Site Recovery from Azure that included a hotfix for additional kernels.

Link: New kernel support for Mobility Agent Hotfix

Running the above hotfix added the kernel needed and got replications running again.