If there were some documents or other text files stored in the BlackBerry backup (*.ipd) you can recover and extract them using the phoneMiner software.
Convert BlackBerry backup (pre 2012) to Adobe Portable document format.
We have found 2 software records in our database eligible for .ipd to .pdf file format conversion.
Microsoft Windows software - convert ipd to pdf on Windows
A backup and recovery software for smartphones
Convert from ipd 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 ipd to pdf. 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.
A conversion utility for BlackBerry backups