MicroStation DGN file compatibility between V7, V8, V8i and CONNECT Edition
MicroStation CONNECT edition is built on the same V8 file format as V8 2004, XM and V8i were. You can create a DGN in any V8 file version and open in any other V8 file version without any issue.
If you are running anything along with MicroStation, such as a vertical or companion product, on top of MicroStation you will want to check the compatibility between those products. Some of those products may not have backwards compatibility. You will want to verify with the support team for that vertical or companion product.
MicroStation opens design files from all previous editions. When you open a V7 design file, you have the option of either upgrading the file to V8 DGN file format or opening it read-only. If you want to work with V7 design files in the current version of MicroStation but need to maintain backward compatibility, you have two choices:
Upgrade newly opened V7 design files to the new format, but save them when done making changes as V7 files in which the graphic representation is maintained.
Configure MicroStation to operate in V7 workmode, in which MicroStation permits the opening of V7 design files for write access but disables functionality that is not backward-compatible.