Microsoft Switches Azure App Service for Linux to Ubuntu for New Runtimes

NOTE: This article was published yesterday (30/10/2025), but due to some technical issues it went offline.

Microsoft is updating the foundation of its Azure App Service for Linux by moving new code-based runtimes to Ubuntu. The update, announced today, will apply to all upcoming major versions, including .NET 10, Python 3.14, Node 24, PHP 8.5, and Java 25. Microsoft says that it expects to roll it out over the next few months.

Existing Debian-based stacks will continue to function as-is, meaning developers won’t face any forced migrations. Microsoft says the change to Ubuntu will offer a more stable and forward-compatible foundation. This helps operational parity across deployment and scaling tools like Oryx, GitHub Actions, and Azure CLI.

Why Microsoft Is Moving to Ubuntu

According to Microsoft, Ubuntu provides faster upstream updates and inherits Debian’s extensive package ecosystem. This allows Azure to adopt modern toolchains and libraries more predictably, improving compatibility and unlocking access to newer dependencies. Additionally, Ubuntu’s Long-Term Support (LTS) releases offer a five-year maintenance cycle.

What Developers Need to Know

For developers running existing apps, no action is required. However, new apps or upgrades to the mentioned runtimes will automatically use Ubuntu-based images. Microsoft advises teams to double-check any native packages installed during builds or startup, as Ubuntu may offer newer versions or slightly different package names.