diff --git a/CHANGES.md b/CHANGES.md
index 2335f98..7f0a364 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,6 @@
+Changes in version 2017-06-20 (20170620)
+- Fix conversation of columns (cols,rows) from string to int
+
 Changes in version 2017-06-19 (20170619)
 - Change field name game_snakes_database.cols => usedcols
 - Change field name game_snakes_database.rows => usedrows
diff --git a/db/upgrade.php b/db/upgrade.php
index f24bccb..244083d 100644
--- a/db/upgrade.php
+++ b/db/upgrade.php
@@ -41,6 +41,29 @@
 
 defined('MOODLE_INTERNAL') || die();
 
+
+/**
+ * Copies a string field to int field
+ *
+ * @param int $oldversion
+ */
+function mpgame_db_copy_string_to_int( $table, $from, $to) {
+    global $CFG, $DB;
+
+    $sql = "SELECT id,$from,$to FROM {$CFG->prefix}$table";
+    $recs = $DB->get_records_sql( $sql);
+    foreach ($recs as $rec) {
+        $val = intval( $rec->$from);
+        if ($rec->$to == $val) {
+            continue;
+        }
+        $updrec = new stdClass;
+        $updrec->id = $rec->id;
+        $updrec->$to = $val;
+        $DB->update_record( $table, $updrec);
+    }
+}
+
 /**
  * Upgrades database
  *
@@ -1556,7 +1579,7 @@ function xmldb_game_upgrade($oldversion) {
         $dbman->change_field_type($table, $field);
     }
 
-    if ($oldversion < ($ver = 2017061604)) {
+    if ($oldversion < ($ver = 2017062002)) {
         $table = new xmldb_table('game_cross');
         $field = new xmldb_field('usedrows', XMLDB_TYPE_INTEGER, '3', XMLDB_UNSIGNED, null, null, '0', 'id');
         if (!$dbman->field_exists($table, $field)) {
@@ -1565,15 +1588,14 @@ function xmldb_game_upgrade($oldversion) {
 
         $field = new xmldb_field('rows', XMLDB_TYPE_INTEGER, '3', XMLDB_UNSIGNED, null, null, '0', 'id');
         if ($dbman->field_exists($table, $field)) {
-            $sql = "UPDATE {$CFG->prefix}game_cross SET usedrows=rows";
-            $DB->execute( $sql);
+            mpgame_db_copy_string_to_int( 'game_cross', 'rows', 'usedrows');
             $dbman->drop_field($table, $field);
         } else {
             $dbman->add_field($table, $field);
         }
     }
 
-    if ($oldversion < ($ver = 2017061604)) {
+    if ($oldversion < ($ver = 2017062002)) {
         $table = new xmldb_table('game_cross');
         $field = new xmldb_field('usedcols', XMLDB_TYPE_INTEGER, '3', XMLDB_UNSIGNED, null, null, '0', 'id');
         if (!$dbman->field_exists($table, $field)) {
@@ -1582,15 +1604,14 @@ function xmldb_game_upgrade($oldversion) {
 
         $field = new xmldb_field('cols', XMLDB_TYPE_INTEGER, '3', XMLDB_UNSIGNED, null, null, '0', 'id');
         if ($dbman->field_exists($table, $field)) {
-            $sql = "UPDATE {$CFG->prefix}game_cross SET usedcols=cols";
-            $DB->execute( $sql);
+            mpgame_db_copy_string_to_int( 'game_cross', 'cols', 'usedcols');
             $dbman->drop_field($table, $field);
         } else {
             $dbman->add_field($table, $field);
         }
     }
 
-    if ($oldversion < ($ver = 2017061901)) {
+    if ($oldversion < ($ver = 2017062002)) {
         $table = new xmldb_table('game_snakes_database');
         $field = new xmldb_field('usedrows', XMLDB_TYPE_INTEGER, '3', XMLDB_UNSIGNED, null, null, '0', 'id');
         if (!$dbman->field_exists($table, $field)) {
@@ -1599,15 +1620,14 @@ function xmldb_game_upgrade($oldversion) {
 
         $field = new xmldb_field('rows', XMLDB_TYPE_INTEGER, '3', XMLDB_UNSIGNED, null, null, '0', 'id');
         if ($dbman->field_exists($table, $field)) {
-            $sql = "UPDATE {$CFG->prefix}game_snakes_database SET usedrows=rows";
-            $DB->execute( $sql);
+            mpgame_db_copy_string_to_int( 'game_snakes_database', 'rows', 'usedrows');
             $dbman->drop_field($table, $field);
         } else {
             $dbman->add_field($table, $field);
         }
     }
 
-    if ($oldversion < ($ver = 2017061901)) {
+    if ($oldversion < ($ver = 2017062002)) {
         $table = new xmldb_table('game_snakes_database');
         $field = new xmldb_field('usedcols', XMLDB_TYPE_INTEGER, '3', XMLDB_UNSIGNED, null, null, '0', 'id');
         if (!$dbman->field_exists($table, $field)) {
@@ -1616,8 +1636,7 @@ function xmldb_game_upgrade($oldversion) {
 
         $field = new xmldb_field('cols', XMLDB_TYPE_INTEGER, '3', XMLDB_UNSIGNED, null, null, '0', 'id');
         if ($dbman->field_exists($table, $field)) {
-            $sql = "UPDATE {$CFG->prefix}game_snakes_database SET usedcols=cols";
-            $DB->execute( $sql);
+            mpgame_db_copy_string_to_int( 'game_snakes_database', 'cols', 'usedcols');
             $dbman->drop_field($table, $field);
         } else {
             $dbman->add_field($table, $field);
@@ -1626,3 +1645,4 @@ function xmldb_game_upgrade($oldversion) {
 
     return true;
 }
+
diff --git a/version.php b/version.php
index 6d0ce40..6b37fe8 100644
--- a/version.php
+++ b/version.php
@@ -35,7 +35,7 @@ if (!isset( $plugin)) {
 }
 
 $plugin->component = 'mod_game';  // Full name of the plugin (used for diagnostics).
-$plugin->version   = 2017061901;  // The current module version (Date: YYYYMMDDXX).
+$plugin->version   = 2017062002;  // The current module version (Date: YYYYMMDDXX).
 $plugin->requires  = 2010112400;  // Requires Moodle 2.0.
 $plugin->cron      = 0;           // Period for cron to check this module (secs).
 $plugin->release   = '2017-06-19';