Europe/Moscow has changed:
"I have made a decision to cancel the move back to 'winter' time starting from autumn this year", Russian president Dmitry Medvedev said on Tuesday, February 8, 2011. The new legislation eliminates the yearly switch between standard time and daylight saving time.
So, timezone.offset() should return +04:00, not +03:00. And because dst is not observed, timezone.dst() should return false.