Strange message in log file

[FalCT60]

Hello,
I sometimes happen to browse the log file, just for curiosity.
This time, I found something that puzzles me, the following line :
1390446.534: Error - Unable to load setting created with a later version of Bibble.
All my plugins being up-to-date as well as ASP, I can't figure what's wrong.
Any idea ?
TIA,
J.-Luc