fix typo

Signed-off-by: Simon L. <szaimen@e.mail.de>

readme.md

@@ -641,7 +641,7 @@ See [multiple-instances.md](./multiple-instances.md) for some documentation on t
 Nextcloud features a built-in bruteforce protection which may get triggered and will block an ip-address or disable a user. You can unblock an ip-address by running `sudo docker exec --user www-data -it nextcloud-aio-nextcloud php occ security:bruteforce:reset <ip-address>` and enable a disabled user by running `sudo docker exec --user www-data -it nextcloud-aio-nextcloud php occ user:enable <name of user>`. See https://docs.nextcloud.com/server/latest/admin_manual/configuration_server/occ_command.html#security for further information. **Please note:** If you do not have CLI access to the server, you can now run docker commands via a web session by using this community container: https://github.com/nextcloud/all-in-one/tree/main/community-containers/container-management
 
 ### How to switch the channel?
-You can switch to a different channel like e.g. the beta channel or from the beta channel back to the latest channel by stopping the mastercontainer, removing it (no data will be lost) and recreating the container using the same command that you used initially to create the mastercontainer. You simply need to change the last line `ghcr.io/nextcloud-releases/all-in-one:latest` to `ghcr.io/nextcloud-releases/all-in-one:beta` and vice versa.
+You can switch to a different channel like e.g. the beta channel or from the beta channel back to the latest channel by stopping the mastercontainer, removing it (no data will be lost) and recreating the container using the same command that you used initially to create the mastercontainer. You simply need to change the last line `ghcr.io/nextcloud-releases/all-in-one:latest` to `ghcr.io/nextcloud-releases/all-in-one:beta` and vice versa. ⚠️ In some rare occurrences, you might need to run `docker pull ghcr.io/nextcloud-releases/all-in-one:latest` or `docker pull ghcr.io/nextcloud-releases/all-in-one:beta` first before being able to use the image.
 
 ### How to update the containers?
 If we push new containers to `latest`, you will see in the AIO interface below the `containers` section that new container updates were found. In this case, just press `Stop containers` and `Start and update containers` in order to update the containers. The mastercontainer has its own update procedure though. See below. And don't forget to back up the current state of your instance using the built-in backup solution before starting the containers again! Otherwise you won't be able to restore your instance easily if something should break during the update.