Drupal 8.x

Im updating several sites from Drupal 8.8.8 and  Drupal 8.6 (something). Updating to Drupal 8.9.6

and get this error:

Mismatched entity and/or field definitions

The following changes were detected in the entity type and field definitions.

Is it possible to have a field in a product type which is hidden, or a group of fields, and when the user clicks a plus sign the fields are displayed?  Because I have too many fields, some users may want this extra data, however it doesn't look good if all fields are displayed by default.

Hello,

I'm new to Drupal and I'm trying to create a new promotion offer and install it. I've copied the code from here which I found linked from these docs. I've created a OrderItemDiscountToFixed.info.yml and zipped the two files together.

Buen día compañeros,

Tengo un sitio ya en Drupal 8 y el cliente quiere un LMS (e-learning) en este, encontré una distribución que se llama "Opigno LMS", todo funciona muy bien, pero ya tengo nodos, taxonomías y demás en el sitio actual, ¿Cómo me recomiendan hacer el paso de esta información a Opigno?.

De antemano, le doy gracias a quien me pueda dar alguna sugerencia o guía y me disculpo si el tema no va en esta seccion.

Muchas gracias.

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Translation with Google, sorry, my English is not good

Hi,

How can I print/display the uid/username of the current user in drupal 8? I would have got this in drupal 7 as below:

<?php global $user; ?>
<?php if ($user->uid) : ?>
<?php print ($user->name); ?>
<?php print ($user->uid); ?>
<?php endif; ?>

Many thanks