Update details: OnixS FIX Support Pack update for CME iLink Trading - Order Handling Flag Tag 1031 is mandatory.
Effective Sunday, November 17, 2019 (trade date Monday, November 18), in conjunction with the Futures Industry Association (FIA) Execution Code Schema initiative, CME Globex will require the current iLink FIX tag 1031-CustOrderHandlingInst on applicable CME iLink 2.x order entry messages. With this change, in-scope CME iLink messages without tag 1031-CustOrderHandlingInst or with an invalid value in the tag will be rejected.
Updated individual FIX Dialect files, which reflect the corresponding changes, can be downloaded from here:
FIX Dialect Download authentication credentials
All FIX Dialects are session-level dialects. This requires explicit dialect specification while creating message and session objects. You can find more information about session-level FIX dialects for .NET, C++ or Java.