The change back is next weekend (rather than the first weekend of April which I think is normal). Unfortunately IB's backfill servers were programmed with change back this weekend so on SPI at least you miss the first hour when backfilling. I presume stocks are the same but I don't subscribe. I contacted IB and they are on it now. The changes have now been made in the US server but we probably won't see anything different until tomorrows data. I don't know if Mon & Tue will backfill correctly tomorrow or not. If they don't and you want the data for the first hours pm me and I'll post the data as a zipped text file here.