Det siteres fra versjonsinformasjonen på typo3.org.
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Here are some of the most important bugfixes:
A bug in the database parser has been fixed. It has made it impossible to create sys_refindex through the Install Tool if $TYPO3_CONF_VARS[SYS][multiplyDBfieldSize] in localconf.php was greater than one.
If you are using this setting, please run Install Tool -> Database Analyser -> Compare again.
Some small fixes to localization view in the Backend Module Web->List have been implemented (bug #4013)
Mails sent by $TSFE->plainMailEncoded are now encoded correctly (bug #1268)
Fixed a bug to make tabbing with new skin possible in textareas (bug #4076)
Filled static_tsconfig_help with new content of core documents. They existed up to TYPO3 3.8 but not in early 4.0 versions. In 4.0.2, the little icon near TypoScript edit fields (TypoScript object browser, Page TSconfig, ...) will now again show the correct reference-content for their respective documents.
A tiny security enhancement to indexed_search has been made: The search word was not escaped correctly so a prepared URL (e.g. referenced in an email) could potentially contain some unwanted JavaScript code.
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[1] TYPO3 4.0.2 wiki: http://wiki.typo3.org/index.php/TYPO3_4.0.2
[2] Arbeidsflyt for lanseringer: http://typo3.org/teams/core/resources/release-workflow
[3] TYPO3 installering og oppgradering: http://wiki.typo3.org/index.php/Upgrade
Komplett oversikt over endringene finnes i filen ChangeLog i TYPO3s kildemappe.