🚀 Backend Versions

When deploying an app, you can select a backend version from a dropdown in the deployment wizard. Each backend version defines the runtime environment your app runs in, including the Python version, Streamlit version, and a set of pre-installed packages.

Version Format

Each backend version is displayed in the following format:

<backend_version> - Python <python_version> + Streamlit <streamlit_version>

For example: 1.15.2 - Python 3.13 + Streamlit 1.51

This means:

• Backend version (1.15.2): The release version of the base Docker image that powers your app. Newer backend versions may include updated pre-installed packages, bug fixes, and infrastructure improvements.
• Python version (3.13): The version of the Python interpreter. Different Python versions offer different language features and performance characteristics.
• Streamlit version (1.51): The version of the Streamlit framework used to run your app.

Choosing a Version

Starting with backend version 1.15.0, each release is available in multiple Python variants. Currently, the following Python versions are offered:

Python Version	Notes
3.10	Default. Most widely compatible with third-party packages. Recommended if you are unsure.
3.11	Faster execution in many workloads (10–60% speedup over 3.10). Good balance of compatibility and performance.
3.13	Latest stable Python release. Best performance and newest language features, but some packages may not yet support it.

Recommendations

• Stick with the default (Python 3.10) if your app relies on packages that may not yet support newer Python versions, or if you want maximum compatibility.
• Choose Python 3.11 or 3.13 if you need better performance or want to use newer Python language features, and you have verified that your dependencies support the chosen version.
• Use an older backend version only if you need to match a previously tested environment for stability. Older versions remain available in the dropdown.

Pre-installed Packages

All backend versions ship with the same set of pre-installed packages regardless of the Python variant. These packages are available immediately without adding them to the Packages field or requirements.txt:

• streamlit
• pandas
• numpy
• matplotlib
• plotly
• scikit-learn
• seaborn
• graphviz
• deepmerge
• python-dotenv
• keboola.component
• streamlit-aggrid
• streamlit-keboola-api
• streamlit_authenticator (pinned to 0.3.1)
• toml

To add packages beyond this list, specify them in the Packages field (for code deployment) or in a requirements.txt file (for Git repository deployment). Custom packages are installed on top of the pre-installed set and will not conflict with it.

Tip

If you need to pin a specific version of a pre-installed package, you can override it by specifying the desired version in the Packages field or in your requirements.txt.

Release Changelog

Below is a summary of changes in each backend version. This information is published here because the source repository is private.

1.15.2

Released: February 9, 2026

• Improved AgGrid Enterprise License integration (license key is now extracted automatically from configuration).

1.15.1

Released: February 4, 2026

• CI/CD improvements for multi-image build pipeline.

1.15.0

Released: February 4, 2026

• Python version selection: Backend images are now available in multiple Python variants (3.10, 3.11, 3.13). Previously, only Python 3.10 was available.
• All dependencies are locked per Python variant for reproducible builds.

1.14.1

Released: January 6, 2026

• Fixed an issue with public IP address auto-detection that could cause startup problems in certain network configurations.

1.14.0

Released: December 18, 2025

• Added support for custom PIP repositories in the app configuration, allowing installation of packages from private or alternative package indexes.

1.13.3

Released: December 16, 2025

• Improved package installation reliability using uv package manager.

1.13.2

Released: December 10, 2025

• Fixed environment file formatting issue that could cause configuration parsing errors.

1.13.1

Released: November 28, 2025

• Fixed an issue where Python commands were not properly routed through the uv package manager.

1.13.0

Released: November 26, 2025

• KBC_URL and KBC_TOKEN are now automatically injected into secrets.toml, making them accessible via st.secrets["kbc_url"] and st.secrets["kbc_token"].
• Improved configuration and secrets handling from config.json.

1.12.1

Released: November 2025

• Switched CI/CD pipeline to GitHub Actions.
• Added automatic semantic version releases.

1.12.0

Released: November 2025

• Replaced pip with uv for significantly faster package installation and dependency resolution.
• Performance optimizations for container startup.