I just upgraded our Connections environment from 4 to 4.5. Unfortunately it didn’t run as smoothly as expected.
I did a side-by-side migration (no application artifacts export) and copied all content stores to the new server
A really nasty problem was that all activities file uploads could not be accessed after the upgrade 🙁
So I checked logs and the DB tables and found out that the storetype of activities uploads changed from filesystem to filestore
-> everytime I tried to download pre-migration files Connections did a lookup for the storetype filesystem which was not defined in oa-config.xml
Fixup was easy, just change the storetype in oa-config.xml to filesystem
If you uploaded files to activities after migration but before changing oa-config.xml you have to define a second storetype in oa-config.xml or you can go to your DB2 server and change the field STORETYPE of all new files in table ACTIVITIES.OA_CONTENTREF to filesystem.