Are my Paratext 7 projects compatible with Paratext 8?

Yes and No. Although Paratext 8 Scripture files are stored on your hard drive in the same USFM format as in Paratext 7.x, there are a number of different types of data that are also synchronized between users. This requires the use of a new Send/Receive server. Paratext 7 projects must go through a one way migration to Paratext 8 and are stored in a new My Paratext 8 Projects folder. After the migration, data can only be shared between them by exporting and importing books manually between the two programs.