CMX is legacy and read-only here
CMX is an older vector format. It can usually be opened and converted from, but it's long obsolete, so there's no modern encoder to create new CMX files.
Looking for CDR to CMX? Here's why CMX isn't an output option — and the modern formats to use.
We don't create CMX files — it's a legacy format that's effectively read-only. Here's what to convert to instead.
CMX is an older vector format. It can usually be opened and converted from, but it's long obsolete, so there's no modern encoder to create new CMX files.
For a file that opens everywhere, convert your CDR to SVG, PDF or EPS instead.
CDR is CorelDRAW’s native vector format for logos, layouts and print artwork — proprietary to Corel software.
How to open CDR opens in CorelDRAW; convert images to CDR to join a Corel workflow.
Full CDR format guide