You can open older NDIF disk images using Finder, then open the Apple Disk Utility and convert it to a DMG format.
Convert Apple NDIF disk image to Apple Mac disk image.
We have found one software suitable in our database for this conversion.
Apple macOS / Mac OS X software - convert ndif to dmg on OS X
A disk utility distributed with Mac OS X / macOS operating system, Apple Disk Utility offers tool for configuration and format of new disk partitions, mount disk images, create, burn, or convert disk images.
Convert from ndif file
|Yes, Apple Disk Utility supports ndif file conversion as a source file type.||Yes||No||No||No||No||No||Yes|
to dmg file
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.