June 14th was the last day to send trades in the MAS DTCC Legacy environment for the first Dry Run.Unlike what was done under EMIR Refit by the main Trade Repositories, DTCC is performing a Dry Run to migrate data from the Legacy to the Rewrite environment, in order to ensure trades format is valid. DTCC gave clear instructions: the trades must comply with the ISO XML standard and certain characters are prohibited. This will avoid what many customers have experienced under EMIR Refit, ie. data partially migrated to the Refit environment, which created side effects (in particular, the inability to send valuations). We welcome the Dry Run initiative from DTCC and are excited to get the first results on June 18th. Another data migration Dry Run based on production data is expected later in July or August. This one will look more like a dress rehearsal.