There are three major reasons why an update might generate error messages.
1. The private space is working just fine without any errors. Only the public site is messed up. This is quite normal... What has happened, is that certain "functions" in SPIP have been modified (otherwise there would have been no need for an update); at the same time, the pages on the public site are stored for a certain amount of time in a cache directory. When you perform an update, it can sometimes occur that the pages on the public site (calculated and generated before the update) employ certain functions that don’t work the same any more after the update.
The easiest solution to this: just empty the cache. Go to the "Configuration" option on the administrator’s menu bar and click on the "Empty the cache" option. When the page displays, you have the option to empty either the page cache or the image cache - in this current scenario, you will want to empty the page cache.
2. You have retrieved and deployed the most recent beta version buried somewhere on our servers in order to see what it looks like.
If you don’t fully understand PHP and/or MySQL, this is just simply a really bad idea. The beta versions are currently under development and not complete for any number of reasons. On some days, if you’re lucky, you might find one that’s relatively stable; on other days, they might well contain all manner of unfinished work that could still be full of undiscovered bugs.
Two scenarios are possible:
- you have made a backup of your database (through "Configuration" - "Site maintenance", and then using the "Backup/restore the database" option) before the unfortunate update; in this case, remain on that same configuration page and completely delete the database (use the "Delete the database" tab). Reinstall the previous version of SPIP (important: this must be the same version as the one that you made your backup with), and then reinstall your site from your backup;
- you don’t have a backup of your database... oops, big mistake. If you’re not comfortable and capable to play around with code and data, the best thing to do is to wait a few days for the next beta version, in the valiant hope that it is more stable than the dodgy one you currently have loaded (generally speaking, the beta versions don’t remain totally unstable for a long time; there always comes a moment, sooner or later, when they function as they ought to; but sometimes the GUI interface can still be a bit messy...).
3. After updating SPIP, you wanted to reinstall the backup of your database that you made before the update. It really still is a mystery why so many people regularly want to entertain such a nutty idea... , but there you go, such is human nature!
We have dedicated a special page carefully explaining how to "correctly" perform an update - PLEASE make your best efforts to follow that procedure to avoid any and all problems.
Whenever SPIP changes version, the provisioning of new functions and improving the system overall will often require us to modify the structure of the database, i.e. change the way that the data used by your site are stored internally. So wanting to reinstall an old backup of the data into a new version of SPIP is very much like trying to put round pegs into square holes.
The only "clean" solution to recover from this situation: navigate to the "Database backup/restore" administration page in the private zone, and completely delete the database. Install the old version of SPIP (all versions of SPIP are always maintained in the archives), and restore the old database backup. Once you’ve done that, you can then re-run the SPIP upgrade, and the update routine itself will make the necessary modifications to database running your site.
Also bear in mind that any plugins you may be using may also well be dependent on the version of SPIP that you’re running. Make sure you install the correct versions of those plugins to match the database structure before, during and after your update of the SPIP engine itself.