I’m not sure if I did something or not, but my logs are showing always the current boot and then before half year ago. There are no logs of last 24 hours, last week or previous boot.
But there were some indestructible corrupted old logs, so I deleted them manually from /var/log/journal/. After every restart, there are logs only for the current boot. I don’t remember if I messed up with journal configuration file. Should I change something?