diff --git a/client/3rd-prebuilt b/client/3rd-prebuilt
index 527b52f0..ae4db58c 160000
--- a/client/3rd-prebuilt
+++ b/client/3rd-prebuilt
@@ -1 +1 @@
-Subproject commit 527b52f08cac102a6386a1fb49f365b4f861c9c2
+Subproject commit ae4db58c73b8be07abcddc42295fd92d84d768f7
diff --git a/client/android/wireguard/src/main/kotlin/org/amnezia/vpn/protocol/wireguard/Wireguard.kt b/client/android/wireguard/src/main/kotlin/org/amnezia/vpn/protocol/wireguard/Wireguard.kt
index 634bc5cd..42a27de4 100644
--- a/client/android/wireguard/src/main/kotlin/org/amnezia/vpn/protocol/wireguard/Wireguard.kt
+++ b/client/android/wireguard/src/main/kotlin/org/amnezia/vpn/protocol/wireguard/Wireguard.kt
@@ -126,14 +126,14 @@ open class Wireguard : Protocol() {
         configData.optStringOrNull("H2")?.let { setH2(it.toLong()) }
         configData.optStringOrNull("H3")?.let { setH3(it.toLong()) }
         configData.optStringOrNull("H4")?.let { setH4(it.toLong()) }
-        configData.optStringOrNull("I1")?.let { setI1(it.toString()) }
-        configData.optStringOrNull("I2")?.let { setI2(it.toString()) }
-        configData.optStringOrNull("I3")?.let { setI3(it.toString()) }
-        configData.optStringOrNull("I4")?.let { setI4(it.toString()) }
-        configData.optStringOrNull("I5")?.let { setI5(it.toString()) }
-        configData.optStringOrNull("J1")?.let { setJ1(it.toString()) }
-        configData.optStringOrNull("J2")?.let { setJ2(it.toString()) }
-        configData.optStringOrNull("J3")?.let { setJ3(it.toString()) }
+        configData.optStringOrNull("I1")?.let { setI1(it) }
+        configData.optStringOrNull("I2")?.let { setI2(it) }
+        configData.optStringOrNull("I3")?.let { setI3(it) }
+        configData.optStringOrNull("I4")?.let { setI4(it) }
+        configData.optStringOrNull("I5")?.let { setI5(it) }
+        configData.optStringOrNull("J1")?.let { setJ1(it) }
+        configData.optStringOrNull("J2")?.let { setJ2(it) }
+        configData.optStringOrNull("J3")?.let { setJ3(it) }
         configData.optStringOrNull("Itime")?.let { setItime(it.toInt()) }
     }
 
diff --git a/client/android/wireguard/src/main/kotlin/org/amnezia/vpn/protocol/wireguard/WireguardConfig.kt b/client/android/wireguard/src/main/kotlin/org/amnezia/vpn/protocol/wireguard/WireguardConfig.kt
index 7a968844..2dfbbae8 100644
--- a/client/android/wireguard/src/main/kotlin/org/amnezia/vpn/protocol/wireguard/WireguardConfig.kt
+++ b/client/android/wireguard/src/main/kotlin/org/amnezia/vpn/protocol/wireguard/WireguardConfig.kt
@@ -83,21 +83,21 @@ open class WireguardConfig protected constructor(
             appendLine("jmax=$jmax")
             appendLine("s1=$s1")
             appendLine("s2=$s2")
-            appendLine("s3=$s3")
-            appendLine("s4=$s4")
+            s3?.let { appendLine("s3=$it") }
+            s4?.let { appendLine("s4=$it") }
             appendLine("h1=$h1")
             appendLine("h2=$h2")
             appendLine("h3=$h3")
             appendLine("h4=$h4")
-            appendLine("i1=$i1")
-            appendLine("i2=$i2")
-            appendLine("i3=$i3")
-            appendLine("i4=$i4")
-            appendLine("i5=$i5")
-            appendLine("j1=$j1")
-            appendLine("j2=$j2")
-            appendLine("j3=$j3")
-            appendLine("itime=$itime")
+            i1?.let { appendLine("i1=$it") }
+            i2?.let { appendLine("i2=$it") }
+            i3?.let { appendLine("i3=$it") }
+            i4?.let { appendLine("i4=$it") }
+            i5?.let { appendLine("i5=$it") }
+            j1?.let { appendLine("j1=$it") }
+            j2?.let { appendLine("j2=$it") }
+            j3?.let { appendLine("j3=$it") }
+            itime?.let { appendLine("itime=$it") }
         }
     }
 
@@ -107,21 +107,10 @@ open class WireguardConfig protected constructor(
         if (jmax == null) throw BadConfigException("Parameter jmax is undefined")
         if (s1 == null) throw BadConfigException("Parameter s1 is undefined")
         if (s2 == null) throw BadConfigException("Parameter s2 is undefined")
-        if (s3 == null) throw BadConfigException("Parameter s3 is undefined")
-        if (s4 == null) throw BadConfigException("Parameter s4 is undefined")
         if (h1 == null) throw BadConfigException("Parameter h1 is undefined")
         if (h2 == null) throw BadConfigException("Parameter h2 is undefined")
         if (h3 == null) throw BadConfigException("Parameter h3 is undefined")
         if (h4 == null) throw BadConfigException("Parameter h4 is undefined")
-        if (i1 == null) throw BadConfigException("Parameter i1 is undefined")
-        if (i2 == null) throw BadConfigException("Parameter i2 is undefined")
-        if (i3 == null) throw BadConfigException("Parameter i3 is undefined")
-        if (i4 == null) throw BadConfigException("Parameter i4 is undefined")
-        if (i5 == null) throw BadConfigException("Parameter i5 is undefined")
-        if (j1 == null) throw BadConfigException("Parameter j1 is undefined")
-        if (j2 == null) throw BadConfigException("Parameter j2 is undefined")
-        if (j3 == null) throw BadConfigException("Parameter j3 is undefined")
-        if (itime == null) throw BadConfigException("Parameter itime is undefined")
     }
 
     open fun appendPeerLine(sb: StringBuilder) = with(sb) {