It should be possible to import older Evernote databases (*.enb) even to the latest version of the program by using the File → Import → EverNote 2.x Database option. After that you can export the database as an *.exb format.
Convert Evernote 2.x database to Evernote database file.
We found 3 software records in the database related to .enb to .exb file format conversion.
Microsoft Windows software - convert enb to exb on Windows
A small and handy program for quick notes
Convert from enb file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned enb to exb. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert enb to exb on OS X
Mac version of the popular note making app
Blackberry mobile phones and devices software - convert enb to exb on Blackberry
A personal organizer for BB