diff --git a/bdk-kotlin/aar/src/androidTest/java/org/bitcoindevkit/bdk/AndroidLibTest.kt b/bdk-kotlin/aar/src/androidTest/java/org/bitcoindevkit/bdk/AndroidLibTest.kt
index 0dbaa2a..9a3e7ba 100644
--- a/bdk-kotlin/aar/src/androidTest/java/org/bitcoindevkit/bdk/AndroidLibTest.kt
+++ b/bdk-kotlin/aar/src/androidTest/java/org/bitcoindevkit/bdk/AndroidLibTest.kt
@@ -54,7 +54,9 @@ class AndroidLibTest {
 
     @Test
     fun new_address() {
-        val address = bdkFfi.new_address(wallet)
+        val pointer = bdkFfi.new_address(wallet)
+        val address = pointer.getString(0)
+        bdkFfi.free_string(pointer)
         //println("address created from kotlin: $address")
         assertEquals(address, "tb1qzg4mckdh50nwdm9hkzq06528rsu73hjxxzem3e")
         Log.d("new_address", "new address: $address")
diff --git a/bdk-kotlin/jar/src/main/java/org/bitcoindevkit/bdk/Lib.kt b/bdk-kotlin/jar/src/main/java/org/bitcoindevkit/bdk/Lib.kt
index f4ef503..3a7fe45 100644
--- a/bdk-kotlin/jar/src/main/java/org/bitcoindevkit/bdk/Lib.kt
+++ b/bdk-kotlin/jar/src/main/java/org/bitcoindevkit/bdk/Lib.kt
@@ -12,7 +12,7 @@ interface Lib : Library {
 
     // void free_string (
     //    char * string);
-    fun free_string(string: String)
+    fun free_string(string: Pointer)
 
     // WalletPtr_t * new_wallet (
     //    char const * name,
@@ -27,7 +27,7 @@ interface Lib : Library {
 
     // char * new_address (
     //    WalletPtr_t * const * wallet);
-    fun new_address(wallet: WalletPtr_t): String
+    fun new_address(wallet: WalletPtr_t): Pointer
 
     // void free_wallet (
     //    WalletPtr_t * wallet);
diff --git a/bdk-kotlin/jar/src/test/java/org/bitcoindevkit/bdk/LibTest.kt b/bdk-kotlin/jar/src/test/java/org/bitcoindevkit/bdk/LibTest.kt
index 799163e..0947557 100644
--- a/bdk-kotlin/jar/src/test/java/org/bitcoindevkit/bdk/LibTest.kt
+++ b/bdk-kotlin/jar/src/test/java/org/bitcoindevkit/bdk/LibTest.kt
@@ -42,7 +42,9 @@ class LibTest {
 
     @Test
     fun new_newaddress_wallet() {
-        val address = bdkFfi.new_address(wallet)
+        val pointer = bdkFfi.new_address(wallet)
+        val address = pointer.getString(0)
+        bdkFfi.free_string(pointer)
         //println("address created from kotlin: $address")
         assertEquals(address, "tb1qzg4mckdh50nwdm9hkzq06528rsu73hjxxzem3e")
     }