Release 3.3.0 -- quality 19 Quality 19 is now decoded and encoded, extending the measured range to 0..19. Purely additive; it was previously refused. K = q - 2 confirmed at 19 over four independent probe patterns, with both neighbouring values excluded on every one. Decoding verified end to end: our decode of the reference's own 9-level quality-19 file matches the reference decoder on every pixel of a 2560x2560 image. The probe needed to be sixteen times smaller in area than estimated: a constant image holds the coarsest LL band at 127, which is not the ceiling -- a 512-pixel checkerboard reaches 229, surviving one further shift step. Quality 20 now has a precise requirement rather than an estimate: 10 pyramid levels, so a probe at least 5120 pixels on its short side. 573 tests. Conformance unchanged.