You provided very helpful info previously. I wonder if you can help again.
I wanted the Imp to take readings at 0600 UTC, so I used server.sleepuntil(6,0). The result was that the Imp came to life at about 0559, took the readings, and went back to sleep until 0600, which was a few seconds later. So I get two sets of readings a day, not the desired single set.
What I assume was happening was that the internal timer was running a little fast, causing the early wakeup. Then the wifi connection corrects the timer, which leads to the second wakeup.
How can I get around this?