System Setup and Software Installation Guide for Cisco NCS 1010, IOS XR Releases

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Downgrade software version

Updated: June 17, 2026

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Use this procedure to downgrade software version. It supports IOS XR software maintenance by outlining the required actions, inputs, or verification points for the activity.

Use this task to downgrade software version.

Downgrade the current software version to a previous software release in case of an upgrade failure or based on requirement.

Note

When downgrading the software image from release 24.4.x to an earlier version, we recommend to manually downgrade the line card firmware as well to prevent any impact on various functionalities.

Before you begin

Check the FPD status and ensure that all the FPDs are in CURRENT state. 

RP/0/RP0/CPU0:ios#show hw-module location all fpd

If the FPDs are not in CURRENT state, upgrade the FPDs.

RP/0/RP0/CPU0:ios#upgrade hw-module location all fpd all
After all the FPDs are upgraded, reload the NCS 1010. 
RP/0/RP0/CPU0:ios#reload location all
Proceed with reload? [confirm]

After the NCS 1010 reloads, check that all the FPDs are in

CURRENT

state.

Follow these steps to downgrade software version.

Procedure

1.

Determine the supported target versions to downgrade from the current version.

Example:

RP/0/RP0/CPU0:ios#show install upgrade-matrix

View the hardware or software limitations, and bridging SMUs required for the version downgrade. For more information about checking compatibility between the current and target versions, see

Downgrading Packages:

Customers can also downgrade user-specified packages (for example, xr-telnet). This is separate from downgrading the entire XR version, but an ISO for an earlier version of XR is used instead of a newer ISO.

2.

Back up the file system of the current version for recovery purposes.

Example:

Copy the running configuration to the harddisk: directory on the NCS 1010: 
RP/0/RP0/CPU0:ios#copy running-config harddisk:/running_config-<mmddyyyy>
Copy the running configuration to a remote server: 
RP/0/RP0/CPU0:ios#scp harddisk:/ running_config user@<ip-address>:<location>
3.

Download the target version from the Software Download Center.
4.

You can either install from the remote repository or copy the ISO image file to the /harddisk: of the NCS 1010.

Example:

RP/0/RP0/CPU0:ios#scp root@<ip-address>:/<dir>/1010-x64-release.iso harddisk:
5.

Verify that the MD5 checksum of the copied target file matches with the MD5 value of the source on the Software Download Center.

Example:

RP/0/RP0/CPU0:ios#show md5 file /harddisk:/1010-x64-<target-version>.iso
6.

Install the base image to downgrade the system.

Example:

RP/0/RP0/CPU0:ios#install replace /harddisk:/1010-x64-release.iso

The image is installed, the changes are applied through a reload or a restart of the system, and commits the changes. However, you do not have control over the timing of the reload or restart —these occur as soon as the package operation completes and the system is ready.

RP/0/RP0/CPU0:ios#install package replace /harddisk:/1010-x64-release.iso
          
RP/0/RP0/CPU0:ios#install apply [reload | restart]
  • Option 1: Install ISO without control over reload timing.

    If you want to control when your system reloads (management of a network outage), we recommend that you schedule a downgrade window and perform an install replace operation, letting the system reload without intervention.

  • Option 2: Install ISO with control over reload timing.

    1. Install the image.

    2. Apply the changes.

      You can use either the reload or restart options based on the file that is installed. To determine whether a reload or restart is required, check the output of show install request command. The output indicates the required actions.
7.

After the base image is downgraded, install the additional packages. For more information, see Install additional RPMs and bug fixes.

During an install operation, if the system reboots unexpectedly or an apply by reload results in the system failing to boot, it automatically recovers to its software state before the current transaction.

Downgrade to a previously installed package

Use this task to downgrade to a previously installed package.

You can downgrade a package to a previously installed version. By default, the subsequent previous version (version previous to the current version) is installed. Also, you can downgrade the software to a specific version of interest. To remove a bug fix RPM from the installed packages, downgrade the package to a version where the fix was not applied.

Note

While downgrading, you can choose any previous version, including the base version of the RPM. However, when downgrading a bug fix RPMs, ensure that you also consider all dependencies of the current version.

Bug fix RPM is an upgrade to the existing package. The action of removing a bug fix RPM either removes the entire feature, or fails if the package is mandatory.

You can use the show install fixes deactivate command to view information related to removing a bug fix. This command provides information such as the package changes, other bug fixes that get deactivate, instructions for adding packages missing for the bug fix removal to be successful, command for removing the bug fix, and any recommendations, if applicable. See the following example:

Note

You can specify any number of DDTS seperated by a space in the show install fixes deactivate command. For example, to know the recommendations for removing bug fix for ABC123, DEF456, and GHI789, you can use show install fixes deactivate ABC123 DEF456 GHI789 command.

The following example shows the package xr-telnet-24.3.1v1.0.1 is downgraded to xr-telnet-24.3.1v1.0.0. The path to source can be a local location or a configured repository.

Before you begin

Ensure you have access to the previously installed package and its source.

Follow these steps to downgrade to a previously installed package.

Procedure

1.

Downgrade the package using one of the following options:

Example:

RP/0/RP0/CPU0:ios#install package downgrade xr-telnet
          
RP/0/RP0/CPU0:ios#install apply [reload | restart]
          
RP/0/RP0/CPU0:ios#install source <path-to-source> xr-telnet-24.3.1v1.0.0
          
<install>
 <packages>
   <packagename>xr-telnet-24.3.1v1.0.0
            xr-telnet-24.0.11v1.0.0
            xr-telnet-24.4.1v1.0.0
</packagename>
 </packages>
   <source>file://<path-to-source>/</source>
</install>
  • Downgrade the package where the fix was applied. When multiple older versions of the package are present in the configured repositories, the immediate previous version of the package is installed. Use caution when using this command as the current version of the package is removed completely.

    Apply the changes.

    Note

    To identify whether to reload the NCS 1010 or restart the affected processes as part of the apply operation, use either show install history last transaction verbose command or show install request command.

  • Install a specific earlier version of the optional package. The changes are applied automatically.
    Note

    An automatic change may trigger a reload of the NCS 1010 depending on the package being downgraded.

  • Use install RPC on the Cisco-IOS-XR-install-act.yang data model. Here is an example usage with a local repository:

    The package version xr-telnet-24.3.1v1.0.1 xr-telnet-24.0.11v1.0.1 xr-telnet-24.3.1v1.0.1 is downgraded to xr-telnet-24.3.1v1.0.0 xr-telnet-24.0.11v1.0.0 xr-telnet-24.4.1v1.0.0.
2.

Commit the operation.

Example:

RP/0/RP0/CPU0:ios#install commit
Note

The install commit command must be executed immediately after software upgrades or SMU installations and before applying any new configuration changes or powering off the device to prevent loss of changes upon reboot.