diff --git a/src/io.c b/src/io.c
index ffe8e2fdf..563cc8c25 100644
--- a/src/io.c
+++ b/src/io.c
@@ -142,6 +142,7 @@ void* wolfSSH_GetIOWriteCtx(WOLFSSH* ssh)
         #include <errno.h>
     #elif defined(WOLFSSH_ZEPHYR)
         #include <zephyr/net/socket.h>
+        #include <zephyr/version.h>
     #else
         #include <sys/types.h>
         #include <errno.h>
@@ -258,6 +259,15 @@ void* wolfSSH_GetIOWriteCtx(WOLFSSH* ssh)
 #elif defined(WOLFSSL_NUCLEUS)
     #define SEND_FUNCTION NU_Send
     #define RECV_FUNCTION NU_Recv
+#elif defined(WOLFSSH_ZEPHYR)
+    #if KERNEL_VERSION_NUMBER >= 0x40100
+        /* Zephyr 4.1 dropped the POSIX socket names; zsock_ is always there. */
+        #define SEND_FUNCTION zsock_send
+        #define RECV_FUNCTION zsock_recv
+    #else
+        #define SEND_FUNCTION send
+        #define RECV_FUNCTION recv
+    #endif
 #else
     #define SEND_FUNCTION send
     #define RECV_FUNCTION recv