> So the Unicode database format itself has not changed ?

No. The changes listed below have no impact afai-have-tested.

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F. Unicode Character Database Changes

The detailed listing of all changes to the contributory data files of the Unicode Character Database for Version 5.2.0 can be found in UAX #44, Unicode Character Database. The most significant changes include:

    * There are new case-related properties in DerivedCoreProperties.txt and DerivedNormalizationProps.txt. The new case-related derived properties are NFKC_Casefold, Case_Ignorable, Cased, Changes_When_Lowercased, Changes_When_Uppercased, Changes_When_Titlecased, Changes_When_Casemapped, Changes_When_Casefolded, and Changes_When_NFKC_Casefolded.
    * Contributory is considered to be a distinct status for a Unicode character property. Contributory properties are neither normative nor informative. The status of all character properties is listed in the property table in UAX #44, Unicode Character Database.
    * Two new joining groups, FARSI YEH and NYA, were added. These new joining groups may require an update to implementations of Arabic shaping rules.
    * There is a new data file in the Unicode Character Database, CJKRadicals.txt, which maps the radical numbers used in the Unicode Radical-Stroke Index to the actual Unicode code points for the corresponding radicals. Unlike other files, the first field is not a code point number.
    * The Unihan.txt file in Unihan.zip is split into 8 separate files within the zip file, organized by category. See UAX #38, Unicode Han Database (Unihan) for details.
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See also:
http://www.unicode.org/reports/tr44/tr44-4.html#Change_History