There are no issues at all connecting a Midas console system running G2.6 (XL8) or G2.6.1 (PRO3, PRO6, or PRO9) with a system running G3.4.6.  They will run absolutely fine together.  If you are using DL431, or DL231 to clock between the two systems, then these can be running either versions of software.  We would however advise that all IO boxes are upgraded to G3.4.6 as any software bugs that are fixed on them will be included in the latest software.  There are also no issues using Generic AES50 connections between the two systems.

To upgrade an IO Box, you can use the IO Updater that can be found on any of the IO Box download pages from the Midas website.  The IO Updater is another option so avoiding the necessity of getting a console out of its flight case and using the console updater method.