Issue #5784: Cannot test wbits=0 unless we know we have zlib v1.2.3.5
diff --git a/Doc/library/zlib.rst b/Doc/library/zlib.rst
index 1e2df00..9cffe27 100644
--- a/Doc/library/zlib.rst
+++ b/Doc/library/zlib.rst
@@ -160,6 +160,7 @@
must include a zlib header and trailer.
* 0: Automatically determine the window size from the zlib header.
+ Only supported since zlib 1.2.3.5.
* −8 to −15: Uses the absolute value of *wbits* as the window size
logarithm. The input must be a raw stream with no header or trailer.