Calendar Warning

This should be fun: Microsoft warns of calendar problem.

For three weeks this March and April, Microsoft Corp. warns that users of its calendar programs ''should view any appointments... as suspect until they communicate with all meeting invitees.''

Wow, that's sort of jarring -- is something treacherous afoot?

Actually, it's a potential problem in any software that was programmed before a 2005 law decreed that daylight-saving time would start three weeks earlier and end one week later, beginning this year. Congress decided that more early evening daylight would translate into energy savings.

Software created earlier is set to automatically advance its timekeeping by one hour on the first Sunday in April, not the second Sunday in March (that's March 11 this year).

Checking my calendar, I see that I'll be flying to the MVP Summit in Redmond on March 11. I wonder if the airlines will be all messed up?