diff --git a/res/values/non_localizable_custom.xml b/res/values/non_localizable_custom.xml
index a981094e4..0b8446b57 100644
--- a/res/values/non_localizable_custom.xml
+++ b/res/values/non_localizable_custom.xml
@@ -34,7 +34,7 @@
     <bool name="show_statusbar_only_on_dialer">true</bool>
 	<bool name="lock_statusbar">false</bool>
 	<bool name="emoticons_in_messages">true</bool>
-	<bool name="only_display_username_if_unknown">true</bool>
+	<bool name="only_display_username_if_unknown">true</bool> <!-- Display username for all sip addresses (if not in contact and display name empty) -->
 	<bool name="display_messages_time_and_status">true</bool> <!-- Used to show the time of each message arrival -->
 	<bool name="display_time_aside">false</bool> <!-- if display_messages_time = true, display time on the side of the message instead of below -->
 	
diff --git a/src/org/linphone/LinphoneUtils.java b/src/org/linphone/LinphoneUtils.java
index 822a3fbe7..97af9bda3 100644
--- a/src/org/linphone/LinphoneUtils.java
+++ b/src/org/linphone/LinphoneUtils.java
@@ -29,13 +29,12 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 
 import org.linphone.core.LinphoneAddress;
 import org.linphone.core.LinphoneCall;
 import org.linphone.core.LinphoneCall.State;
 import org.linphone.core.LinphoneCore;
+import org.linphone.core.LinphoneCoreFactory;
 import org.linphone.mediastream.Log;
 import org.linphone.mediastream.Version;
 import org.linphone.mediastream.video.capture.hwconf.Hacks;
@@ -68,19 +67,15 @@ public final class LinphoneUtils {
 	private LinphoneUtils(){}
 
 	private static boolean preventVolumeBarToDisplay = false;
-	private static final String sipAddressRegExp = "^(sip:)?(\\+)?[a-z0-9]+([_\\.-][a-z0-9]+)*@([a-z0-9]+([\\.-][a-z0-9]+)*)+\\.[a-z]{2,}(:[0-9]{2,5})?$";
-	private static final String strictSipAddressRegExp = "^sip:(\\+)?[a-z0-9]+([_\\.-][a-z0-9]+)*@([a-z0-9]+([\\.-][a-z0-9]+)*)+\\.[a-z]{2,}$";
+	//private static final String sipAddressRegExp = "^(sip:)?(\\+)?[a-z0-9]+([_\\.-][a-z0-9]+)*@([a-z0-9]+([\\.-][a-z0-9]+)*)+\\.[a-z]{2,}(:[0-9]{2,5})?$";
+	//private static final String strictSipAddressRegExp = "^sip:(\\+)?[a-z0-9]+([_\\.-][a-z0-9]+)*@([a-z0-9]+([\\.-][a-z0-9]+)*)+\\.[a-z]{2,}$";
 
 	public static boolean isSipAddress(String numberOrAddress) {
-		Pattern p = Pattern.compile(sipAddressRegExp);
-		Matcher m = p.matcher(numberOrAddress);
-		return m != null && m.matches();
+		return LinphoneCoreFactory.instance().createLinphoneAddress(numberOrAddress) != null;
 	}
 	
 	public static boolean isStrictSipAddress(String numberOrAddress) {
-		Pattern p = Pattern.compile(strictSipAddressRegExp);
-		Matcher m = p.matcher(numberOrAddress);
-		return m != null && m.matches();
+		return isSipAddress(numberOrAddress) && numberOrAddress.startsWith("sip:");
 	}
 	
 	public static String getUsernameFromAddress(String address) {