diff --git a/src/version.c b/src/version.c
index 42d5889..3dc537d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    6,
+/**/
     5,
 /**/
     4,
@@ -1328,9 +1330,9 @@
 	if (highest_patch())
 	{
 	    // Check for 9.9x or 9.9xx, alpha/beta version
-	    if (isalpha((int)vers[3]))
+	    if (SAFE_isalpha((int)vers[3]))
 	    {
-		int len = (isalpha((int)vers[4])) ? 5 : 4;
+		int len = (SAFE_isalpha((int)vers[4])) ? 5 : 4;
 		sprintf((char *)vers + len, ".%d%s", highest_patch(),
 							 mediumVersion + len);
 	    }