There are a few things to note when upgrading. Game Jackal v4 is a new version of the application, and not technical upgrade. This mean v4 can be installed alongside v3. When you do install v4, it will look for any existing v3 profiles and move them to the v4 application's "Profile Library" directory (this is a bug as they should have been copied). The issue here is that your v3 profiles will disappear and you will need to copy them back to the v3 folder if you wish to continue using v3. To do this copy the "Profile Library" directory from v4 to v3. If you uninstall v3 after installing v4, we recommend that you reinstall v4 before rebooting. If your profiles do not appear in v4 (for what ever reason), you can manually copy them by doing the following. Close the v4 application. Next shutdown the Game Jackal server by using the stop option from the Game Jackal start menu group (i.e. Start->SlySoft->Stop service). Next copy all files from the "Profile Library" directory in v3 to the "Profile Library" directory in v4. Finally restart the Game Jackal server using the start option from the Game Jackal start menu group (i.e. Start->SlySoft->Start service). Uninstalling v3 can remove the installed Game Jackal license, you will need to rerun the license application once uninstalled. Regarding compatibility... this is the longest Game Jackal beta program todate (running since early July 2009), however there are always unforeseen issues. If you experience problems upgrading, please post the following information. Version upgrading from? Was v3 uninstalled, and when (i.e. before the v4 installation, or after)? What v3 profiles are not working and the issue they are having. Using v4 are you able to successfully create new profiles. Finally, if you are concerned about upgrading, please backup you profiles first be coping all files in the "Profile Library" folder.