It is important to distinguish between MIDI communications that happen between devices and those that involve a file. The below only tries to clarify the issues related to files.

MIDI 1.0 defines to 'Standard MIDI File' (SMF) formats: 0 and 1. The latest Montage M OS (2.10.1) only works with format 1 files in the MIDI 1.0 format - p.492 of the operation doc:

.mid File     File     .MID  MIDI data stored in the Song and Pattern area of
User memory is saved to a USB flash drive as a
Standard MIDI File (SMF; only in format 1).

MIDI 2.0 defines two new file formats: a 'MIDI Clip File' storing records in the MIDI 2.0 UMP format and a 'MIDI 20 Container File Binary Format' file that acts as a container for multiple clip files.

Currently Montage M neither reads nor writes files in either of the 2 new MIDI 2.0 file formats. That is likely to change in the future but it hasn't yet been disclosed whether the upcoming OS 3.0 release, expected later this month, will include that functionality.

File reader applications designed for MIDI 1.0 won't be able to read or write the two new MIDI 2.0 files until, or unless, they are updated to do so.

It remains to be seen what level of fuctionality file reader applications designed for MIDI 2.0 will have. Some possibilities:

1. read and write both MIDI 2.0 files with full functionality

2. convert a MIDI 2.0 file to a corresponding MIDI 1.0 file

3. read a MIDI 1.0 file and create a corresponding MIDI 2.0 file by embedding the MIDI 1.0 commands in UMP records

4. read a MIDI 1.0 file and convert the MIDI 1.0 commands to corresponding MIDI 2.0 commands and UMP records

The way that numbers 3 and 4 are interpreted and implemented inform the answer to the question: is MIDI 2.0 fully compatible with MIDI 1.0 or not?

Process #3 is essentially just a 'wrapper' for the actual MIDI 1.0 commands. It doesn't interpret or change the commands at all but rather just embeds them in UMP formatted records. Thus a reverse process can reproduce the original MIDI 1.0 file EXACTLY.

Process #4, however, converts the MIDI 1.0 commands to a MIDI 2.0 format. This has data conversion implications regarding the different precision that MIDI 2.0 offers compared with MIDI 1.0. That discussion is for another thread.

Will a pre-MIDI 2.0 instrument be able to read/write/process either of the new MIDI 2.0 file formats? Not likely - they would need a software update that understands the format and would also need a process to extract the embedded MIDI 1.0 commands, if process #3 above was used, or actually convert the MIDI 2.0 file contents to MIDI 1.0 format if process #4 above was used.

The more general solution might be for a 3rd party to provide off-line conversion software rather than actually update existing instruments themselves.