.LDI File

File extension ldi is commonly used for the LDAP Data Interchange Format.

 LDIF is a standard plain text data interchange format for representing LDAP (Lightweight Directory Access Protocol) directory content and update requests. LDIF conveys directory content as a set of records, one record for each object (or entry). It represents update requests, such as Add, Modify, Delete, and Rename, as a set of records, one record for each update request.

This format is used for example in Mozilla Thunderbird as one of the choices when you export address book.

How to open:

You can import address book data from .ldi files to Thunderbird and perhaps some other email clients.

How to convert:

As this format is used to exchange contacts and other data., it is likely that some sort of ldi conversion is possible.