Backend skin
To better support the backend skin “t3skin” which was introduced in TYPO3 4.0, the Template and the Backend Admin module have been adapted.
Secondly the current page was not highlighted in the navigation tree of Internet Explorer 6. This bug has been fixed.
Compatibility issues
The captionSplit.cObject had been removed in version 4.0. For compatibility reasons, it has been added again, though it remains deprecated and should not be used anymore.
In TYPO3 4.0, showpic.php automatically adds default parameters to custom URLs. Some extensions did not like this feature because they want to generate all parameters by themselves. Enabling JSwindow.altUrl_noDefaultParams will now solve this problem for them
FORM submit buttons with images are now valid xhtml.
DBAL
The following changes where made for DBAL (database abstraction layer).
Generally the code hast been cleaned up. The support for oracle was improved. Besides that the used ADOdb has been updated to version 4.90. DBAL now honours the no_pconnect setting.
Importing dumps using the install tool now works, see manual [3] for tips.
Further reading
[1] TYPO3 Installation and upgrading: http://typo3.org/documentation/document-library/installation/doc_inst_upgr/current/
[2] TYPO3 4.0.1 wiki: http://wiki.typo3.org/index.php/TYPO3_4.0.1
[3] DBAL: http://typo3.org/documentation/document-library/extension-manuals/dbal/current/view/
A complete changelog can be found in the TYPO3 source directory. Please have a look at the file ChangeLog for details.
