1. Copy the 'Newtonsoft.Json-v9.dll' file located in 'C:\npo\found\fims\assemblies to c:\npo\dlc\bin\, then re-name the 'Newtonsoft.Json-v9.dll' to 'Newtonsoft.Json.dll'. Note, your FIMS installation may be on another drive other than C on your server. Also note, that even if you do not use DonorCentral, you will still need to do this step.
2. Re-compile FIMS by running the command in Part 7 of the Progress 11 upgrade guide.