YAZ 5.34.3-2 (2024-02-25) is available for download:
"YAZ is a toolkit that allows you to develop software using the ANSI Z39.50/ISO23950 standard for information retrieval.
YAZ (yet another Z39.50 toolkit) is a portable C/C++ programmer's toolkit which supports the development of Z39.50v3 clients and servers. Sample clients and a server are included with the distribution."