Unicode is a character encoding standard that supports most of the world's more common scripts, and includes support for user-defined scripts. Many older applications do not fully support Unicode, so keyboards that are Unicode-based may not work properly in them.

Keyman keyboards can use either Unicode or the older codepage-based formats. Codepage formats usually only support one or at most two writing systems (or scripts). This means, for instance, that in a database you can only use a single language in a given field. Some applications may let you use only a single language in the whole document, when using codepage formats.

Windows 95, 98 and Me also only include limited support for Unicode. A number of applications have introduced support for Unicode input using Keyman on these operating systems. Check the Tavultesoft website for an up-to-date list.

Make sure that you have installed the RichEdit addin (look in Keyman Configuration, Addins tab) as this allows Unicode input in a large number of older applications.

If you are working on Windows 95, 98 or Me, the WordLink addin will allow you to type Unicode into Microsoft Word.

You may find that you can use a Unicode keyboard to enter into another, newer, application, and then use the clipboard to copy and paste text into the older application.