The very next day, Silvia received a letter from the Post Office. Rowan was a known name there, so it was always Silvia's name used during the exchanges.
Post Offices generally did not have private alerts to the receiver. They had to go to the Post Office and ask if they had received anything.
In order not to waste the time of all the spies they sent out, Alterra implemented a standard time of sending and receiving of letters. Anyway, they seemed to still be in the same time zone somehow, despite being a thousand kilometers apart.
Rather, even if it was farther away in Bleulle, the timezone was still the same, so they knew that at least, assuming this place was a globe, it was quite a big bigger a planet than Terran was.
Anyway, Alterra would always send out letters at specific times of the day, except during urgent events like wars, in which case they would order someone to camp in the Post Office at all times.
