Bitnami Stacks are auto contained. All the components are under the installation directory and are not replaceable by system packages.
Bitnami MEAN Stack is only built with PHP 5.6. There is no an official workflow for updating PHP from 5.6 to 7.0 in Bitnami MEAN Stack but we can try.
In order to update from PHP 5.6 to PHP 7.0 you could try to copy it from an existent PHP 7 installation:
- Create a backup of your MEAN Stack
- Stop all services
- Download and install Bitnami LAMP Stack with PHP 7.0
- Stop Bitnami services from LAMP Stack
- Copy recursively the
common folder of the new installation to your MEAN Stack installation
- Remove the
php folder from your MEAN Stack and copy over the
php folder from the new stack to the MEAN Stack
- Uninstall LAMP Stack
- Restart Bitnami services
You can find information about how to perform these steps at the Bitnami MEAN Stack documentation page:
Hope it helps, let me know if it worked for you.