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**API Changes (Backward Incompatible)**
- Introduce ``HyperframeError`` base exception class for all errors raised within hyperframe.
- Change exception base class of ``UnknownFrameError`` to ``HyperframeError``
- Change exception base class of ``InvalidPaddingError`` to ``HyperframeError``
- Change exception base class of ``InvalidFrameError`` to ``HyperframeError``
- Invalid frames with wrong stream id (zero vs. non-zero) now raise ``InvalidDataError``.
- Invalid SETTINGS frames (non-empty but ACK) now raise ``InvalidDataError``.
- Invalid ALTSVC frames with non-bytestring field or origin now raise ``InvalidDataError``.
**API Changes (Backward Compatible)**
- Deprecate ``total_padding`` - use `pad_length` instead.
- Improve repr() output for all frame classes.
- Introduce Frame.explain(data) for quick introspection of raw data.
**Bugfixes**
- Fixed padding parsing for ``PushPromiseFrame``.
- Fixed unchecked frame length for ``PriorityFrame``. It now correctly raises ``InvalidFrameError``.
- Fixed promised stream id validation for ``PushPromiseFrame``. It now raises ``InvalidDataError``.
- Fixed unchecked frame length for ``WindowUpdateFrame``. It now correctly raises ``InvalidFrameError``.
- Fixed window increment value range validation. It now raises ``InvalidDataError``.
- Fixed parsing of ``SettingsFrame`` with mutual exclusion of ACK flag and payload.
**Other Changes**
- Removed support for Python 2.7, 3.4, 3.5, pypy.
- Added support for Python 3.8.