Today we've got a new release of Lotus Notes, IBM Notes 9.0, the first without Lotus in its name.
Upgrading from Notes 8.5.3FP3 is supposed to be smooth as always. But there is a little detail to be taken into account.
If you are a power user with Designer, Admin and multiple plugins installed, Notes 9 installer doesn't like IBM Connections 3.0.1 plug-ins.
If you decide to install the IBM Connections feature in your upgrade process
you'll probably get an installation error with no way back :-)
If you have a look at C:\Lotus\Notes\Data\workspace\logs\error-log-0.xml or a similar file, you´ll find out that the reason was the Connector plugin
Could not install bundle ../../shared/eclipse/plugins/com.ibm.json4j_184.108.40.20630228-1411.jar Bundle "com.ibm.json4j" version "220.127.116.1130228-1411" has already been installed from: update@plugins/com.ibm.json4j_18.104.22.16830228-1411.jar
The solution to this minor inconvenience is to uninstall the plugins from the "Add or remove Programs" option in Control Panel ( Yes, I'm still using XP, and it works fine so far )
Then, just launch the installer again and select the option Repair and everything should be fine now.