I don't think any changes are needed.

None of the removed twig variables are mentioned in the 4.2 documentation.

Deprecations were:

• The Kernel::getRootDir() and the kernel.root_dir parameter have been deprecated

No references to the method or parameter found in the 4.2 documentation.

• The KernelInterface::getName() and the kernel.name parameter have been deprecated

A deprecation notice is already present: https://github.com/symfony/symfony-docs/blob/master/reference/configuration/kernel.rst#kernel-name

• Deprecated the first and second constructor argument of ConfigDataCollector

No references to ConfigDataCollector found in the 4.2 documentation.

• Deprecated ConfigDataCollector::getApplicationName()

No references to this method found in the 4.2 documentation.

• Deprecated ConfigDataCollector::getApplicationVersion()

No references to this method found in the 4.2 documentation.

let's close here then