rlSearch.class.php ... question for refine search

[rosegarden]

I notice the search result for refine search is much better for the new version compared to the old (not keyword search)

For example in the old version, if I search title text for "Apple orange", it will not appear if the title is "xxxx orange yyy apple" or any of either apple or orange is in the title

I have no time to upgrade to new version and I just want to know which line from rlSearch.class.php from new version shall i look out for so i can upload and replace that portion only onto the old version.

I tried replacing the entire file "rlSearch.class.php" from the new version but it break my site.