There was an issue caused by a pool enabling something they were not supposed to until after the Sapling activation. there was a check that was supposed to have stopped that until Sapling, but it had an error and didn't stop it. As a result, the old versions became unable to follow the chain, and wallets that were not upgraded yet stopped progressing because they saw the chain moving forward but could not follow. Pools are coming back, exchange is coming back, no one should have lost anything, and the way to solve it for anyone is to upgrade to 0.4.0 or 0.4.0a. Thank you.