TMG7 and TMG8 are different programs. Both can be installed on the same computer.
TMG8 will use different folders for the program and data than TMG7.
Once you update a project to TMG8, it cannot be opened using TMG7.
If you want to use both programs, you should transfer your projects by backing up in TMG7 and restoring in TMG8.
TMG 5/6 projects must be backed up in those versions and restored in TMG8. TMG4 databases must be imported.
Note that Language Translations and Preferences: Program Options will not be restored from a TMG7 and earlier backup and these files should not be transferred to TMG8 from earlier program versions. If you have a custom language in an earlier version, export it in that program version and import it to TMG8.
Web search config files should probably not be restored since this part of TMG8 has been completely changed.
Edited by Jim Byram, 24 December 2011 - 08:10 AM.