A slight correction – I did have to tweak a little bit of code in OJS to get this all working as it should.
After following the upgrade directions, your OJS install will be left with an entry in the database for the plugins you’ve installed through the Plugin Gallery before, but the plugins won’t be present in your filesystem. Thus OJS as released will report that the plugin is already present and up to date, even though it isn’t.
To get it to permit you to re-install the plugins you were using with a prior release of OJS, you’ll need to apply a patch. This is currently undergoing code review at Plugins already installed in database but not filesystem cannot be re-installed · Issue #2956 · pkp/pkp-lib · GitHub (but it’s a simple enough change that you can apply it with high confidence). After that you’ll be able to hit the Upgrade button inside the plugin gallery to re-add each plugin to your OJS.
Regards,
Alec Smecher
Public Knowledge Project Team