diff --git a/kw11-l.cpp b/kw11-l.cpp
index f94e4f3..4fb7c74 100644
--- a/kw11-l.cpp
+++ b/kw11-l.cpp
@@ -216,19 +216,18 @@ uint8_t kw11_l::get_lf_crs()
 	return rc;
 }
 
-#if IS_POSIX
-json_t *kw11_l::serialize()
+JsonDocument kw11_l::serialize()
 {
-	json_t *j = json_object();
+	JsonDocument j;
 
-	json_object_set(j, "CSR", json_integer(lf_csr));
+	j["CSR"] = lf_csr;
 
 	return j;
 }
 
 kw11_l *kw11_l::deserialize(const json_t *const j, bus *const b, console *const cnsl)
 {
-	uint16_t CSR = json_integer_value(json_object_get(j, "CSR"));
+	uint16_t CSR = j["CSR"];
 
 	kw11_l *out  = new kw11_l(b);
 	out->lf_csr  = CSR;
@@ -236,4 +235,3 @@ kw11_l *kw11_l::deserialize(const json_t *const j, bus *const b, console *const
 
 	return out;
 }
-#endif
diff --git a/kw11-l.h b/kw11-l.h
index f7f8fcc..d0e418c 100644
--- a/kw11-l.h
+++ b/kw11-l.h
@@ -1,6 +1,7 @@
 // (C) 2018-2024 by Folkert van Heusden
 // Released under MIT license
 
+#include <ArduinoJson.h>
 #include <atomic>
 #include <thread>
 
@@ -42,10 +43,8 @@ public:
 
 	void     show_state(console *const cnsl) const override;
 
-#if IS_POSIX
-	json_t *serialize();
-	static kw11_l *deserialize(const json_t *const j, bus *const b, console *const cnsl);
-#endif
+	JsonDocument serialize();
+	static kw11_l *deserialize(const JsonDocument j, bus *const b, console *const cnsl);
 
 	void     begin(console *const cnsl);
 	void     operator()();