Various versions of database projects from Microsoft Access (.ade, .acccdp) can only be reliably handled in the original tool, no 3rd party software will help you. So if you are hoping to transform compiled older .ade projects to newer .accdp projects, you will have to use MS Access 2007 or later.
Convert Microsoft Access compiled project to Microsoft Access 2007/2010 project file.
We found one software available in the database for this conversion.
Microsoft Windows software - convert ade to accdp on Windows
A relational database management system from Microsoft Office
Convert from ade file format
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.