Important
It has been superseded by zlib-ng and Slicer/zlib-ng, the corresponding Slicer fork with minor customizations to streamline integration.
zlib version 1.2.3 was originally released on July 18, 2005. Since at least 2012, CTK and 3D Slicer have relied on this CMake-enabled fork of zlib 1.2.3.
In the years since, official and modernized versions of zlib have become available on GitHub:
- madler/zlib — the canonical zlib source
- zlib-ng/zlib-ng — a performance-oriented fork with full CMake support.
For more context on this transition, see Slicer pull request #6708.