--- a/Cargo.toml
+++ b/Cargo.toml
@@ -59,10 +59,6 @@
 ssh_key_from_memory = []
 vendored = []
 vendored-openssl = ["openssl-sys/vendored"]
-zlib-ng-compat = [
-    "libz-sys/zlib-ng",
-    "libssh2-sys?/zlib-ng-compat",
-]
 
 [target."cfg(unix)".dependencies.openssl-sys]
 version = "0.9"