EDIT: so people can see that it has already occured.

Friendly PSA from the preparedness queen to mastodonians in Denmark:

Please be aware that 7. May at noon, the yearly test of the public warning system will take place. That means that at noon both the physical air sirens will be tested and also that the mobile warning system will push loud alarms to your phone.

If you for any reason or other have a hidden phone, please don't forget to turn it off.

Read more here: https://www.sirenen.dk/en/national-test