APCu is basically a stripped down version of APC that only includes the data caching code, and is designed to work in tandem with OpCache if you need data caching.

There is no as such implementation of APCu inside Magento's own framework or autoloading process. But we can use the implementation done by composer to improve autoloading process.

According to composer's own documentation;

This option adds an APCu cache as a fallback for the class map. It will not automatically generate the class map though, so you should still enable Level 1 optimizations manually if you so desire.

Whether a class is found or not, that fact is always cached in APCu, so it can be returned quickly on the next request.

Reference - https://getcomposer.org/doc/articles/autoloader-optimization.md#optimization-level-2-b-apcu-cache

APCu is basically a stripped down version of APC that only includes the data caching code, and is designed to work in tandem with OpCache if you need data caching.

There is no as such implementation of APCu inside Magento's own framework or autoloading process. But we can use the implementation done by composer to improve autoloading process.

According to composer's own documentation;

This option adds an APCu cache as a fallback for the class map. It will not automatically generate the class map though, so you should still enable Level 1 optimizations manually if you so desire.

Whether a class is found or not, that fact is always cached in APCu, so it can be returned quickly on the next request.

EDIT :

If you want to use APCu cache in composer for an instance you have to run composer update or install whatever you are running using the --apcu-autoloader param

For this case, as you will be running composer update to upgrade to the new version you should be running

composer update --apcu-autoloader 

Reference - https://getcomposer.org/doc/articles/autoloader-optimization.md#optimization-level-2-b-apcu-cache

APCu is basically a stripped down version of APC that only includes the data caching code, and is designed in tandem with OpCache if you need data caching.

There is no as such implementation of APCu inside Magento's own framework or autoloading process. But we can use the implementation done by composer to improve autoloading process.

According to composer's own documentation;

This option adds an APCu cache as a fallback for the class map. It will not automatically generate the class map though, so you should still enable Level 1 optimizations manually if you so desire.

Whether a class is found or not, that fact is always cached in APCu, so it can be returned quickly on the next request.

Reference - https://getcomposer.org/doc/articles/autoloader-optimization.md#optimization-level-2-b-apcu-cache

APCu is basically a stripped down version of APC that only includes the data caching code, and is designed to work in tandem with OpCache if you need data caching.

There is no as such implementation of APCu inside Magento's own framework or autoloading process. But we can use the implementation done by composer to improve autoloading process.

According to composer's own documentation;

This option adds an APCu cache as a fallback for the class map. It will not automatically generate the class map though, so you should still enable Level 1 optimizations manually if you so desire.

Whether a class is found or not, that fact is always cached in APCu, so it can be returned quickly on the next request.

Reference - https://getcomposer.org/doc/articles/autoloader-optimization.md#optimization-level-2-b-apcu-cache