Route "entity.event.version_history" does not exist

File code "mymodule.links.task.yml"

event.view:
route_name: entity.event.canonical
base_route: entity.event.canonical
title: 'View'

event.edit_form:
route_name: 'entity.event.edit_form'
base_route: entity.event.canonical
title: 'Edit'

event.delete_form:
route_name: entity.event.delete_form
base_route: entity.event.canonical
title: Delete
weight: 10

entity.event.revision_history:
route_name: entity.event.revision_history
base_route: entity.event.canonical
title: 'Revisions'
weight: 20

Is "event" a custom entity that you created?

Hi @cilefen
Yes, this custom module was created to display event contents, it was working with previous versions of drupal, even version 10.0.9. As of version 10.1.0, I get this error. Something has changed in this new version for the creation of the "View", "Edit", "Delete" and "Revision" tabs, which correspond to the ".links.task.yml" file. Need help.

If I had to guess this is https://www.drupal.org/node/3160443 → and your entity definition has been missing this route.

Hi @cilefen, I didn't understand well, you say to configure the routes in the .routing.yml file of the custom module? This module doesn't have a rem_core.routing.yml file, I'm trying to understand how it works.

The community would want to see more of your custom module to offer assistance.

ok, I am sending the zipped module in attachment (tor_event)

I think this entity is missing a required route so this is a support request.

ok, what else changed so that this was working before in version 10.0 and not working in version 10.1 ?

Probably https://www.drupal.org/node/3160443 →

The tor_entities custom module works together with the tor_event module, it is also attached. I'm still trying to understand what happened. Thanks a lot for your help

The solution was actually the one indicated by @cilefen in post #6. I didn't really understand this, I found it strange that a change in the article's comment would correct this.
For me the solution was to just insert:

* "revision" = \Drupal\Core\Entity\Routing\RevisionHtmlRouteProvider::class,

in the file comment "docroot/modules/custom/tor_album/src/Entity/Album.php"

It looks like this:

/**
* handlers = {
*...
* route_provider = {
*...
* "revision" = \Drupal\Core\Entity\Routing\RevisionHtmlRouteProvider::class,
* }
* }
*/