v1.2.0

What's Changed

HDLC / FD protocol

• Implemented missing HDLC ABM protocol features (proper SABM/UA/DISC/DM/FRMR handling)
• Added P/F bit enforcement in ABM mode and UI (Unnumbered Information) frame support
• Implemented SREJ (Selective Reject) S-frame support
• NRM mode: fixed P/F burst handling, CR bit handling, and frame filtering in disconnected state
• Fixed connection breakdown when nothing was sent for >= keep-alive timeout (#40)
• Large internal refactoring of the FD layer to simplify and stabilize NRM mode support

C++ / Python bindings

• Fixed several C++ wrapper reliability issues
• Updated and improved Python bindings
• Updated language standard to C++17

Tests & CI

• Added many new unit tests: NRM mode, S-Frame RR, SREJ, ABM features, and 19 additional C++ wrapper tests
• Fixed CI pipeline: pin setuptools<78 for ESP-IDF v4.3 compatibility

Documentation

• Major README overhaul
• Updated Doxygen documentation for v1.2.0
• Updated copyrights to 2025

Full Changelog: v1.1.1...v1.2.0