# Azure CLI 2.51.0 (August 01, 2023) introduces Python UserWarning of cryptography for extensions
The cryptography UserWarning on Azure CLI 2.51.0: the CLI was running 32-bit Python on 64-bit Windows on Microsoft-hosted agents. Migrate to the 64-bit Azure CLI (see the install docs section 'Migrate to 64-bit Azure CLI'); GitHub runner images now ship 64-bit by default.
## Context from the issue
gh:Azure/azure-cli#27115: Issue Azure/azure-cli#27115 (closed, 34 comments): ### Describe the bug When Azure CLI 2.51.0 (August 01, 2023) is installed, `arcappliance` extension produces a Python `UserWarning`: > You are using cryptography on a 32-bit Python on a 64-bit Windows Operating System. Cryptography will be significantly faster if you switch to using a 64-bit Python. This leads to PowerShell `RemoteException` which fails Azure Pipelines. We have tried to uninstall 2.51.0 and install 2.50.0, and the error disappears. ### Related command ``` # az extension add --name arcappliance az arcappliance validate hci --config-file $configFilePath --only-show-errors # A no