Public institutions can use any system they want and make the public responsible for reading it.

I remember in some countries there's an official government newspaper. Laws reference publishing things in this paper (e.g. tax rate changes, radio frequency allocations) and the law is that you must follow it once it's published.

In practice the information is disseminated through many channels once it's released in the official newspaper. Mass media reports on anything widely relevant, niche media reports on things nichely relevant, and there's direct communication with anyone directly affected (recipient of a radio frequency allocation) so nobody really subscribes to the official government newspaper, but it's there and if there was a breakdown of communication systems that would be the last resort to ensure you are getting government updates.