Symbolic links is a bad idea on FTP. They are resolved by the client... I think it would also give the false feeling that a new 4.01 file exist when in fact it's the same as 4.00. I better suggest listing files with a simple parsable fiel which lists all files that are part of a Unicode version, with their respective version.
For example the 4.0-Update1 version of this list file would list: BidiMirroring.txt;4.0; CompositionExclusions.txt;4.0; DerivedProperties.txt;4.0; EastAsianWidth.txt;4.0; StandardizedVariants.html;4.0; StandardizedVariants.txt;4.0; ... Saying that these files in 4.0-Update1 take their content from the 4.0 release. There's no need to duplicate files, and no link to create. It documents the set of files that make up a complete Unicode version. Then with the listed versions for each file, it's easy to get the appropriate filename in the appropriate folder... I suggested this a couple of days ago, and even sugegsted adding some properties to differentiate the status of these files in the current version: informative or normative; core or derived according to the current version rules. This is because some files that are informative at some version may become normative later, or because some files which are currently derived from rules, may become basic as the rules to generate them become too complex and infering some properties will become too much errorprone (in that case a derived file becomes a core file)
