Some are classical extensions. Others are specific to Up ! Application System.
| Extension | Meaning | 
| a | Static library for the Unix platform. | 
| avi | Video to the Audio Video (AVI) format from Microsoft. | 
| bat | Script of commands for the Windows platforms. | 
| bmp | Picture to the Bitmap format from Microsoft. | 
| c | Source of a C program. | 
| cpp | Source of a C++ program. | 
| clas class | Class of a Java module. | 
| css | Styles sheet to the Cascading Style Sheet (CSS) format from World Wide Web Consortium (W3C). | 
| csv | Exchange to the Comma Separated Value (CSV) format. | 
| dll | Dynamic library for the Windows platforms. | 
| idl | Interface Definition Language for the Corba or ActiveX objects. | 
| e | Exportations of a source file of a C program. | 
| edi | Exchange to the Electronic Data Interchange For Administration, Commerce and Transport (EDIFACT) format from United Nations. | 
| exe | Executable for the Windows platforms. | 
| gif | Picture to the Graphics Interchange Format (GIF) format CompuServe. | 
| gz | Archive to the Gnu Zip format. | 
| h | Header of a source file of a C program. | 
| hh | Header of a source file of a C++ program. | 
| html | Document to the Hyper Text Markup Language (HTML) format from World Wide Web Consortium (W3C). | 
| idc | Exchange to the IDoc format from Sap. | 
| ini | Initialization of a program. | 
| jav java | Source of a Java program. | 
| jpg jpeg | Picture to the Joint Photographic Experts Group (JPEG) format from Ibm. | 
| lib | Static library for the Windows platforms. | 
| log | Log tracing the activity of the program or a task. | 
| map | Execution trace while activating the Debug parameter. | 
| mp3 | Sound to the Mpeg Layer III (MP3) format. | 
| mpg mpeg | Video to the Motion Jpeg (MPEG) format. | 
| msg | Message to the Rfc 822 format. | 
| nls | Linguistic resources for Up ! Natural Language support. | 
| nlt | Thesaurus for Up ! Natural Language support. | 
| pcl | Document to the Print Code Language (PCL) format from Hewlett Packard. | 
| pcx | Picture to the Pcx format from ZSoft. | 
| Document to the Portable Document Format (PDF) format from Adobe. | |
| pot | Model of document to the Power Point format from Microsoft. | 
| ppt | Document to the Power Point format from Microsoft. | 
| prf | Execution profile produced by Up ! Profiler. | 
| ps | Document to the PostScript format from Adobe. | 
| rtf | Document to the Rich Text Format (RTF) format from Microsoft. | 
| so | Dynamic library for the Unix platforms. | 
| tif tiff tff | Picture to the Tagged Image File Format (TIFF) format from Aldus. | 
| txt | Document without a format. | 
| uar | Archive to the Up ! Archive format. | 
| uei | Data interchange of Up ! Electronic Data Interchange to the binary format. | 
| ugn | Styles sheet of Up ! Graphical Engine to the binary format. | 
| ulg | Log memorizing the modifications made into a persistent warehouse. | 
| uml | Data intrchange of Up ! Mail Service to binary format. | 
| uob | Directory of Up ! Object Request Broker to the binary format. | 
| uof | Archive memorizing some objects of a persistent program. | 
| upc | Vector-based picture of Up ! Picture to the binary format. | 
| upi | Interface of a component or a module written in Up ! 5GL. | 
| upl | Source of a component, a module or a resource written in Up ! 5GL. | 
| usc | Security or licenses profile of Up ! Security Manager to the binary format. | 
| uwf | Archive keeping the objects of a persistent warehouse managed by Up ! Object Management System. | 
| usc | Security archive of Up ! Security Manager. | 
| wav | Sound to the Wave format from Microsoft. | 
| xls | Document to the Excel format from Microsoft. | 
| xlt | Document model to the Excel format from Microsoft. | 
| xml | Document or exchange to eXtended Markup Language (XML) format from World Wide Web Consortium (W3C). | 
| zip | Archive to the Z Lib format. |