Each version of Opus installs in its own directory.
Today I loaded several
copies of pubs of varying complexity made with v5.5. They loaded perfectly with no obvious problems. This time there was no message along the lines of
This was made with an earlier version of Opus. Do you want to save a copy? Can I assume that v6 seems happy to regard v5.5 as a kindred spirit
My next move was to go for broke and using v6, open a complex pub made with v281. Received the warning message, so saved the original file. Conversion went fine, but took about 20 minutes. The only issue encountered was the same as when I converted the same pub from 281 to v4 -- text appearance because of the introduction of antialiasing.