We would like to announce that the upgrade of Plone to v3.3.4 will occur between tomorrow (Friday 19th Feb) and the end of this weekend (Sun 21st Feb). After this upgrade, for each of your websites you will need to do the following:

1. Enter portal_migration in your ZMI and upgrade.
2. Enter portal_quickinstaller in your ZMI and reinstall any products which have been upgraded. We strongly recommend that you do one at a time if you get any errors by trying to do all at once.
3. For each product upgraded, reenter its settings in Site Setup. For example TinyMCE will return to default settings.

During the upgrade your website will still be present, but any attempts to login may return a 502 Service Unavailable error. In the highly unlikely situation that your site dies after the upgrade, please contact us.

Details behind the upgrade:

We have been waiting for v2.0.5 of the varnish web cache to be released before we performed the upgrade of our Plone installation to v3.3.4. This is because that release of varnish finally adds support for the HTTP If-None-Match header which is used by web browsers on Plone sites to tell the web server which version of a web page they already have a copy of by sending its last known ETag. Unfortunately, varnish used to always bypass its cache when it saw such a header which effectively meant that all visitors to any ned Productions Ltd. website who had been here before bypassed the cache (not that this caused much load nor delay, as Zope simply returned a 304 Not Modified).

What that meant in practice was that if we took down Plone for any reason, every visitor who had been before instantly got a 502 Service Unavailable error. Other than stripping If-None-Match support and therefore greatly increasing page load times while visitors navigated our sites, there wasn't much we could do.

With this new support however, we can now take down Plone for up to 24h and varnish will continue to serve out its cached content and so long as the cache has a copy of the page, no one should notice a thing. Obviously enough because logged in users always bypass the cache they will not be able to log in at all during the upgrade. Right now the cache is being populated, so we should be ready to start work tomorrow.

Obviously enough this new feature considerably improves load scalability and load times of changed pages on all ned Productions Ltd. websites. Whereas before Zope always had to be asked to verify an ETag and if it didn't match then Zope  had to deliver a copy of the page, now varnish understands ETags and will handle everything. This should reduce page load times for updated pages by a few hundred milliseconds.

Other new features resulting from this upgrade are mostly bug fixes. Firefox users will see a very substantial improvement in page load times as a bug invoking Java with every page has been fixed. There has been a very rare XSS vulnerability fixed in Zope (not an issue in Plone), and there have been many more bug fixes to TinyMCE and a few other components.