diff --git a/src/com/company/Version.java b/src/com/company/Version.java
index 3c1105c..8f360b1 100644
--- a/src/com/company/Version.java
+++ b/src/com/company/Version.java
@@ -25,6 +25,10 @@ public enum Version {
         final Pattern pattern_dev_release = Pattern.compile("^(\\d).(\\d+).(\\d+)(\\D)(.+)");
         Matcher m ;
 
+        if (!pattern_stable_release.matcher(min).find() || !pattern_stable_release.matcher(last).find()) {
+            throw new Error("VersionCheck: wrong format for min or last version given");
+        }
+
         m = pattern_stable_release.matcher(value);
         if (m.find()) {
 
@@ -60,7 +64,7 @@ public enum Version {
 
     //helper
     // 0 to less
-    // 1 in spectrum
+    // 1 in range
     // 2 at the top
     // 3 above
     private static int correlate(String min, String last, String value){
@@ -68,35 +72,50 @@ public enum Version {
         int i_min = 0, i_last = 0, i_value = 0;
 
         //go down each integer (separated by points) until it is the last one
-        while (value.indexOf(".")>0) {
+        while (value.contains(".")) {
 
             //prepare for checks
-            if (min.indexOf(".") >= 0) i_min = Integer.valueOf(min.substring(0,min.indexOf(".")));
-            if (last.indexOf(".") >= 0) i_last = Integer.valueOf(last.substring(0,last.indexOf(".")));
-            if (value.indexOf(".") >= 0) i_value = Integer.valueOf(value.substring(0,value.indexOf(".")));
+            i_min = Integer.parseInt(min.substring(0,min.indexOf(".")));
+            i_last = Integer.parseInt(last.substring(0,last.indexOf(".")));
+            i_value = Integer.parseInt(value.substring(0,value.indexOf(".")));
 
-            if ( i_min != i_last ) {
-                //check
-                if (i_value < i_min) return 0;
-                if (i_value > i_last) return 3;
+            if (i_value < i_min) return 0;
+            if (i_value > i_last) return 3;
+
+            //check in range correlation
+            int result = correlate(min.substring(min.indexOf(".")+1),last.substring(last.indexOf(".")+1),value.substring(value.indexOf(".")+1));
+
+            if (i_value == i_last) {
+                switch (result){
+                    case 0:
+                        return 0;
+                    case 1:
+                        return 1;
+                    case 2:
+                        if (i_value < i_last ) return 1;
+                        if (i_value == i_last) return 2;
+                    case 3:
+                        return 3;
+                }
+            } else { //value in range
+                return 1;
             }
-
-            //delete checked integer and move on to next one
-            min = min.substring(min.indexOf(".")+1);
-            last = last.substring(last.indexOf(".")+1);
-            value = value.substring(value.indexOf(".")+1);
-
         }
 
-        i_min = Integer.valueOf(min);
-        i_last = Integer.valueOf(last);
-        i_value = Integer.valueOf(value);
+        i_min = Integer.parseInt(min);
+        i_last = Integer.parseInt(last);
+        i_value = Integer.parseInt(value);
 
         //check last integer
+        if (i_min > i_last){
+            if (i_value == i_last) return 2;
+            if (i_value < i_last) return 1;
+        }
         if (i_value < i_min) return 0;
-        if (i_min < i_value && i_value < i_last) return 1;
+        if (i_value >= i_min && i_value < i_last) return 1;
         if (i_value == i_last) return 2;
-        if (i_value > i_last) return 3;
+        return 3;
+    }
 
 
         return 0;