There is no "local code pool override" mechanism anymore. Instead you can use preferences in di.xml
for any class that is instantiated by the Magento object manager, i.e. used via Dependency Injection in Magento classes. This is the equivalent to a class rewrite in Magento 1.
But for classes like Zend_Date
where this is not the case, this is not possible.
However you could create a composer package that loads your own Zend_Date
class before the real one is loaded via autoloading:
composer.json
{
"name": "your/custom-date",
"autoload": {
"files": ["src/lib/Zend/Date.php"]
}
}
src/lib/Zend/Date.php
class Zend_Date
{
...
}
EditEdit: After you edited a composer.json file, run composer dump-autoload
to update the autoloader.