diff --git a/irc/constants.go b/irc/constants.go
index 49bf4c93..20e07b17 100644
--- a/irc/constants.go
+++ b/irc/constants.go
@@ -17,13 +17,13 @@ var (
 	ErrAlreadyDestroyed = errors.New("already destroyed")
 
 	// regexps
-	ChannelNameExpr = regexp.MustCompile(`^[&!#+][[:word:]]{1,63}$`)
+	ChannelNameExpr = regexp.MustCompile(`^[&!#+][\pL\pN]{1,63}$`)
 	NicknameExpr    = regexp.MustCompile(
-		"^[[:alpha:]\\[\\]{}^`][[:word:]\\[\\]{}^`]{1,31}$")
+		"^[\\pL\\[\\]{}^`][\\pL\\pN\\[\\]{}^`]{1,31}$")
 )
 
 const (
-	SEM_VER       = "ergonomadic-1.2.6"
+	SEM_VER       = "ergonomadic-1.2.7"
 	CRLF          = "\r\n"
 	MAX_REPLY_LEN = 512 - len(CRLF)
 
diff --git a/irc/server.go b/irc/server.go
index e9a4d45c..49c5f4ad 100644
--- a/irc/server.go
+++ b/irc/server.go
@@ -407,6 +407,11 @@ func (msg *NickCommand) HandleServer(server *Server) {
 		return
 	}
 
+	if !IsNickname(msg.nickname) {
+		client.ErrErroneusNickname(msg.nickname)
+		return
+	}
+
 	if msg.nickname == client.nick {
 		return
 	}