Not accepting, but this is to save its customers. We all know that bitcoin has an ongoing upgrade now and this will continue. When this action ends, everything will be okay again. Don't get offend.
Yes its true. Of course this is just temporary changes. Bittrex just want our bitcoins to be safe for the upcoming correction. Like what they are saying here in the forum, keep safe your coins in a cold storage to avoid losing of coins.
They're not saying it will really lost but its better to prevent it.
Maybe bittrex will get back to usual after the correction is done.