replace preg_replace with preg_replace_callback

/e is not supported starting with php 7.0

main.php

@@ -34,9 +34,11 @@ while(true) {
                     $delete = true;
                 }
                 if($i == $groupCount AND $delete == false) {
-                    $regex = '#([0-9]{1,3})#e';
-                    $replacement = '("$1" + 1)';
-                    $newName = preg_replace($regex, $replacement, $group['channel_name']);
+                    $regex = '#([0-9]{1,3})#';
+                    $callback = function ($matches) {
+                        return $matches[0]+1;
+                    }
+                    $newName = preg_replace($regex, $callback, $group['channel_name']);
                     createChannel($server, $newName, $sub, $options);
                 }
             }