• Various AAT shaping fixes: legacy mort contextual offsets (which could produce out-of-font glyph IDs), in-place deleted-glyph replacements, and overflow in obsolete offset math.
• Fix Arabic PUA fallback shaping for the isolated lam-alef-maksura ligature.
• Fix float-to-int overflow in avar2 mapping with malformed fonts.
• Harden buffer verification after detecting non-monotone clusters.
• Various COLR v1 fixes: fix handling of .notdef without paint, round alpha consistently, and report the root clip under the font transform.
• Various Glyph-extents fixes: inclusive rounding, and floating-point scaling before rounding so the reported box always covers the glyph.
• Various Subsetting fixes: keep the palt spacing feature by default, raise the repacker MAX_SPACES limit, fix a repacker crash on shared LigatureSet nodes, guard gvar size overflow on 32-bit, and fix the post glyph-name sort comparator on macOS.
• Replace std::sort with an internal quicksort, removing leaked std:: symbols from the libharfbuzz ABI.
• Harden size computations with saturating arithmetic against 32-bit overflow.
• Various improvements to the experimental Rust shaper (HarfRust) and font functions (fontations): honor custom font funcs, key shape plans on features, faster buffer handling, and update to HarfRust 0.8.
• Various fixes to the experimental harfbuzz-gpu and harfbuzz-vector libraries, including a harfbuzz-vector heap buffer overflow and Windows build fixes.
• Map the Hrkt (Katakana or Hiragana) script tag to the kana OpenType tag.
• Build configuration: new HB_CONFIG_OVERRIDE_LAST_H override header, decouple HB_NO_DRAW from HB_NO_CFF, and an optional hb-allocator Cargo feature.
• Various build, CI, and fuzzing fixes.