Open Office was the first legitimate free contender to Microsoft Office, though it has ceded that spotlight in recent years to alternatives like Google Docs, Sheets, and Slides, and its own spinoff product Libre Office. The open source suite includes word processing (Write), spreadsheets (Calc), presentation (Impress), and database management (Base) programs, along with drawing and math apps that don’t have a direct Microsoft corollary.

If you still remember how Microsoft Office looked circa 2003, Open Office’s interface will seem eerily familiar. The component programs make no concessions to the trendy ribbon interface, using only old-school menus and toolbars. That’s good news if you’re still sore over Microsoft’s decade-old UI makeover, but it can take some readjusting if you’re now accustomed to tabbing around your document and spreadsheet programs.

By default, Open Office uses the Open Document standard for native files, but you can change it to save to Microsoft formats, and it can read and write existing Word, Excel, and PowerPoint files. It does so flawlessly most of the time, even with complexly formatted documents like resumes and multi-column newsletters. Occasionally, it will hiccup as when it removed all the embedded images from a Word doc I had open. But those instances usually only require minor tweaks to correct. You can also export files to PDF from all three programs.

Where Open Office diverges from Microsoft’s productivity suite is in collaboration. MS Office’s tight integration with OneDrive and Outlook allows you to easily share and work on files with others without leaving the respective program. Open Office supports document review features like commenting and track-changes, but it has no native cloud storage or email program. It does, however, offer an extension that lets you connect to dozens of third-party cloud storage providers including Box and Google Drive, and the Open Office programs can be configured to work with select open source email clients like Mozilla Thunderbird.

If you just need to work with Microsoft Office formats, and you don’t mind what some would consider a dated interface, Open Office has all the comprehensive formatting and functionality you need. If you need to collaborate with others on those files, though, there are other office alternatives that make it much easier.