Microsoft recently announced that its Azure App Service for Linux service will mainly use Ubuntu as the basic operating system in the future, replacing the previous Debian. According to the latest news, starting from the next versions such as .NET 10, Python 3.14, Node 24, PHP 8.5 and Java 25, they will all be based on Ubuntu, and relevant updates will be gradually rolled out in the next few months.
Microsoft said that choosing Ubuntu has many advantages. First of all, although Ubuntu is based on Debian and can still inherit the Debian ecosystem, Ubuntu has a faster upstream update speed, which helps to adopt the latest tool chains and libraries in a more timely manner. In addition, Ubuntu's LTS (long-term support) version is officially supported by Canonical for five years, two years longer than Debian's full support time. Microsoft also believes that switching to Ubuntu will help optimize image size and improve service reliability and performance.
For existing Azure App Service for Linux applications, Microsoft emphasizes that no action is required and old applications will continue to run on Debian without forced migration. If users create new applications or upgrade to the above new version of the operating environment, the platform will use an Ubuntu-based system by default. Processes such as automated deployment, capacity expansion, diagnostics, and networking will also remain the same and run normally.
Microsoft pointed out that the impact of this change on build behavior is expected to be neutral or positive, and thinning the image can reduce build time and cold start time. It should be noted that when upgrading, users should check the native software packages installed during the build or startup of the application, because some versions or names may be different under Ubuntu. As for supported mainstream development frameworks, Microsoft does not expect major compatibility issues.