diff --git a/app/build.gradle b/app/build.gradle
index 59a66d58..6b4c46c0 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -7,8 +7,8 @@ android {
         applicationId = 'com.tutpro.baresip'
         minSdkVersion 21
         targetSdkVersion 27
-        versionCode = 39
-        versionName = '5.2.0'
+        versionCode = 40
+        versionName = '5.2.1'
         externalNativeBuild {
             cmake {
                 cFlags '-DHAVE_INTTYPES_H'
diff --git a/app/src/main/kotlin/com/tutpro/baresip/AccountActivity.kt b/app/src/main/kotlin/com/tutpro/baresip/AccountActivity.kt
index 8ccff094..f37dafa5 100644
--- a/app/src/main/kotlin/com/tutpro/baresip/AccountActivity.kt
+++ b/app/src/main/kotlin/com/tutpro/baresip/AccountActivity.kt
@@ -402,14 +402,14 @@ class AccountActivity : AppCompatActivity() {
 
     private fun checkDisplayName(dn: String): Boolean {
         if (dn == "") return true
-        val dnRegex = Regex("^[a-zA-Z]([ ._-]|[a-zA-Z0-9]){1,63}\$")
+        val dnRegex = Regex("^([* .!%_`'~]|[+]|[-a-zA-Z0-9]){1,63}\$")
         return dnRegex.matches(dn)
     }
 
     private fun checkAuthUser(au: String): Boolean {
         if (au == "") return true
         val ud = au.split("@")
-        val userIDRegex = Regex("^[a-zA-Z]([._-]|[a-zA-Z0-9]){1,63}\$")
+        val userIDRegex = Regex("^([* .!%_`'~]|[+]|[-a-zA-Z0-9]){1,63}\$")
         val telnoRegex = Regex("^[+]?[0-9]{1,16}\$")
         if (ud.size == 1) {
             return userIDRegex.matches(ud[0]) || telnoRegex.matches(ud[0])