ripple/rippled — pull request #741 by nbougalis (2014-11-26 05:32:23+00:00)
Title: Remove support for deprecated PreviousTxnID field (RIPD-710):

The PreviousTxnID field has been deprecated and should not be used for
transactions that use the field will now be rejected.

The AccountTxnID feature should be used instead by enabling transaction
tracking and specifying a transaction ID at submission. More details
are available at: https://ripple.com/build/transactions/#accounttxnid