Flask 3.0+Python 3.3

Why?

Why is Flask 3.0 incompatible with Python 3.3?

Requirement

Python >=3.8

Selected version

Python 3.3

Evaluation

3.3.7 does not satisfy >=3.8

Conclusion

INCOMPATIBLE

Evidence

CompatHub reports compatibility from upstream sources rather than making unsupported claims of its own.

• PyPI JSON API

  Confidence: HIGH

  https://pypi.org/pypi/Flask/3.0.3/json

  Retrieved 30 August 2026

  Requirement: >=3.8

Python versions

Compatibility is derived from the project's declared Python requirement (>=3.8); it does not mean every version combination has been independently tested.

• 3.2❌
• 3.3❌
• 3.4❌
• 3.5❌
• 3.6❌
• 3.7❌
• 3.8✓
• 3.9✓
• 3.10✓
• 3.11✓
• 3.12✓
• 3.13✓
• 3.14✓
• 3.15✓
• 3.16✓

Other Python versions satisfying this requirement

Flask 3.0 — compatible Python lines tracked in CompatHub

• ✓Python 3.8version lineEOL
• ✓Python 3.9version lineEOL
• ✓Python 3.10version linesupported
• ✓Python 3.11version linesupported
• ✓Python 3.12version linesupported
• ✓Python 3.13version linesupported
• ✓Python 3.14version linesupported
• ✓Python 3.15version line
• ✓Python 3.16version line

Other Flask versions

Only lines with relevant compatibility evidence are listed.

• Flask 3.1
• Flask 3.0
• Flask 2.3
• Flask 2.2
• Flask 2.1
• Flask 2.0
• Flask 1.1
• Flask 1.0

Lifecycle context

Lifecycle status is separate from compatibility. An EOL component can still satisfy a documented version requirement.