Github user HiuKwok commented on a diff in the pull request: https://github.com/apache/commons-lang/pull/340#discussion_r209574053 --- Diff: src/main/java/org/apache/commons/lang3/StringUtils.java --- @@ -5596,8 +5596,8 @@ private static String replace(final String text, String searchString, final Stri } String searchText = text; if (ignoreCase) { - searchText = text.toLowerCase(); - searchString = searchString.toLowerCase(); + searchText = text.toUpperCase(); + searchString = searchString.toUpperCase(); --- End diff -- Hi @kinow, yes you are right after I did try to come up with a draft java main to generate all || most unicode in string and compare it's length between original, toLowerCase() and to UpperCase().  It's seem like no matter which one we pick (toLowerCase || toUpperCase), it would still tend to come up with a incorrect length. Just a quick question what you mean by remove the ```length( )``` mean? Would you mind to specify more on that? Thanks,
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