While upgrading Lotus Quickr 8.0 to 188.8.131.52 (HF4) at a customer site we experienced two problems:
The first thing was that the command "l qptool upgrade -f -a", which you have to do in order to get all places upgraded to the new version, promotes all place managers to super users. So you should check your places afterwards and correct them if necessary. A PMR is opened and currently under investigation. You can see a corresponding message also in the Domino server logs ("Upgrade: Upgrading Place 'Main.nsf', promoting 'CN=xxx yyy' to SuperUser.") if you set a higher log level for the upgrade process (set the variable "QuickPlaceUpgradeLogging=4" in the NOES.INI before running the upgrade command; attention: you will get many messages if you do have many places to upgrade, so be careful by using this parameter).
The other issue was that after upgrading all places the users did not see any documents in the Quickr connectors. The reasons seems to be that "l qptool upgrade -f -a" did not upgrade the places correctly. What worked for us was to issue the command "l qptool upgrade -f -a" again. after the second run all places worked correctly with the connector again. Another PMR was opened for that as well.