Starting on January 5th, 2013 all MPEx accounts that have a zero BTC balance and zero holdings of any kind (including any stocks, shares, options, futures, funds, also including any sums deposited as collateral for option or future issuance) will be disabled. This means you will not be able to use MPEx ("Unrecognized signature. Please email your public key first." error.)
Starting on February 5th, 2013 all MPEx accounts that have been disabled as per above and have not been reinstated will be purged. This means all account data will be deleted. Accounts' signature will be replaced with MPEx's own in our trade history databases. Signed receipts will be discarded. You will not be able to file any claims for anything whatsoever after this date.
In order to reinstate a disabled account you can contact us any time after January 5th, 2013 but before February 5th, 2013. Your account will be re-enabled on request, however, if your balances etc are still zero on February 5th, 2013 your account will still be purged.
This will be a recurring yearly event. Please plan your account management accordingly.