We had a switch from summer to winter time in europe tonight. Sadly Poco::Logger set to local time (both logger itself and the formatter) didn't account for that automatically. The operating system (linux) did. So I observed a peculiar situation: last modified time of the log file was oct 27 12:26 (correct) but the last entry in it was at oct 27 13:26 (sic!). I had to restart that poco based daemon to make the logger account for the time change.
time change from UTC+2 to UTC+1
PS. I understand that this is a beta verion but please fix this in the final release as it doesn't seem to be mentioned in the 1.5.2. changelog.