At around 14:00 (GMT) today WordPress was updated to 4.8.3 and an email like the following should have been received.
[Site Name] Your site has updated to WordPress 4.8.3
Hiya! Your site at https://yourwebsite.com has been updated automatically to WordPress 4.8.3.
No further action is needed on your part. For more on version 4.8.3, see the About WordPress screen:
If you experience any issues or need support, the volunteers in the WordPress.org support forums may be able to help.
You also have some plugins or themes with updates available. Update them now:
The WordPress Team
The update is part of WordPress’ automatic updates performed by default on all WordPress websites. These updates are for security and maintenance purposes, they also update translation files on some websites.
Note you have already been advised that there are plugin and theme updates available and as advised update them now. We also advise you check back regularly for others that haven’t been updated as yet.
If you do not manage your own updates check with your webmaster, or person who is responsible, to ensure they are regularly performing the updates.
Regular updates of your WordPress website are ultimately your responsibility and essential to maintaining a secure online space for you and your visitors.