SQ has decided to change it flight numbers in order not to confuse the travellers with similar sounding flight numbers. Cities affected by this change are :
Well - they've changed the numbers for BLR as well. And the new numbers are more confusing than the old ones At least in the old series all 4xx flights were to India - now you have a few 4xx to India, and a few 5xx to India! Strange, very strange.