If you recently (since 1st of November) experienced error like this one:

please follow this quick fix to get Updater working again:

• Start Fiji
• Go to Help->Update Fiji then click Manage update sites.

• Find QuimP in the list, double-click at address and change http to https

• Press Enter and make sure that checkbox on left is selected. Close updater and restart Fiji.
• If you do not see QuimP group in Plugins menu, go to Manage update sites again and unselect QuimP and then select it again. You should see QuimP files to be installed. Click Apply changes and restart Fiji.