In this setup you can not use any of the new Symfony and Platform features as the legacy bundle ("bridge") is not used for integrating the two system together. So this is more of a first step toward eZ Platform, getting your legacy code to work with eZ Publish 5.x.
If you choose this because of performance concerns setting up a combined setup, recommendation is to move to PHP 7.x when moving to Platform setup which will result in a overall faster setup then a pure legacy setup on PHP 5.x.
Anchor Usingezpublish5.0throughthelegacystackbutrelyingonthenewcontrollerandnewtemplatesystemaswellasthenewkernel. Usingezpublish5.0throughthelegacystackbutrelyingonthenewcontrollerandnewtemplatesystemaswellasthenewkernel.
Using eZ Publish 5.0 with both legacy & platform stack to start to take advantage