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Upgrading to WP 2.0

  • Information on Upgrading.

    Backing up your database is <u>ESSENTIAL</u>

    A guide on Codex can be found here:

    A guide can also be found here:

    The guides may differ slightly but both are safe to use. Please take your time and follow them – and if you are unsure, post here first.

    There have been a huge number of changes (500 +) in the core. Studying Trac will show you all the changes if you are keen on reading that. There is not and will not be a changelog here. It is highly recommended that you fully replace the core files.

    New in 2.0
    Have a read:

    Multi-user blogs
    There have been significant changes to the user levels. If you have different users, you must satisfy yourself how this will affect your blog. If you run any sort of plugin that restricts what different users see or can do depending on their level you must be confident about the upgrade. Check everything – do not come back here complaining about user levels if you have not checked and made absolutely sure you know exactly what will happen. The place you need to check is http://codex.wordpress.org/Roles_and_Capabilities

    Plugins I
    This page has details: http://codex.wordpress.org/User:Matt/2.0_Plugin_Compatibility
    Check FIRST. Please don’t upgrade and then say the plugins do not work. There are many plugins that break. Check first and if you need to contact the author, ask nicely πŸ™‚

    Plugins II
    Deactivate plugins before upgrading. If you do not you may get errors and the advice here will be to delete those plugins. Your choice.

    Problems ?
    If you experience any, post to this thread. Please give us lots of information such as:
    Your site
    Your host
    The precise error
    What you have done to try and mend the blog
    If you really did follow the full upgrade instructions. We can tell you know… πŸ™‚

    Also, do not just say “I have the same problem” as someone else – you probably haven’t – you should state your problem in full, along with what you have done.

    And please remember – all the help you get here is provided by other members.

    (from the wonderful Podz)

Viewing 15 replies - 1 through 15 (of 102 total)
  • allotherplaces


    Thanx Podz

    I have a question about the definition of ‘Multi-user blogs’

    Do you mean like mu.*

    or do you mean like changing: $table_prefix = ‘wp_’ to ‘something_’

    I posted this question at

    thanks for your pre-emptive assistance! πŸ™‚

    Mark (podz)
    Support Maven


    You can change the table_prefix and have several blogs in a single database – that’s still fine.

    But One Install and lots of users ? mu.wordpress.org πŸ™‚



    thanks again podz…

    but to be clear, (i dont want to mess this one up) lets say I have ten multiple ‘blogs_’ running now – and want to try 2.0 on ‘blog03_’ – do I have to back up ALL the others at the same time, or can I just do ‘blog03_’

    thanks again for your patience πŸ™‚

    Mark (podz)
    Support Maven


    10 blogs in one database ?
    And JUST one you want to upgrade ?

    Backup just those tables used by the blog you are going to upgrade. (Though backing them all up is a Good Thing πŸ™‚ )

    Each database and core set of files should be backed up before any upgrade is done. If they are each independently running their own DB, then only #3 needs backing up, but remember, as it’s a current mantra, you can never have enough backups.

    Is it possible for me to do a clean install and then upload a backup from 1.2.2?

    I’m changing the site name (and hence database name) too, so I’m wondering if that would throw all the permalinks off or something.

    Great work with the release and the website guys, I set up a tester at http://yse-uk.com/wp2/, working great.


    A clean install is possible but not entirely in the sense you thought.

    1. BACKUP EVERYTHING, I know it’s been said but just incase πŸ™‚
    2. Delete all files and folders where your old WP install was – EXCLUDING wp-config.php and the wp-content directory.
    3. At this stage, create your new database and upload the sql file you will have got from your database backup.
    4. Go back to your wp-config.php file and modify it to match the new database details.
    6. Upload the new files that come from WP2.0
    7. Run the wp-admin/upgrade.php script.
    8. Go into your admin panel and change the site name in options.

    That should all work πŸ˜€ BACKUP!!!<>

    Working like a charm on my site! πŸ™‚

    I’m having extreme trouble, I restored my 1.5.2 db, and now I can’t access my wp-admin panel so I can de-activate all my plugins before attempting the upgrade again, this is the message I get.

    Fatal error: Cannot redeclare generate_page_rewrite_rules() (previously declared in /home/genius/public_html/wp-includes/functions-post.php:787) in /home/genius/public_html/wp-admin/admin-functions.php on line 559

    “1. BACKUP EVERYTHING, I know it’s been said but just incase πŸ™‚
    2. Delete all files and folders where your old WP install was – EXCLUDING wp-config.php and the wp-content directory.”

    There’s an easier and ‘safer’ way — again backup everything, (obviously, it’s just plain foolishness to do this without a full backup), then rename the original top level wordpress directory (or move it into a new directory). This leaves everything intact (the db included, read on for that), a simple rename & 5 seconds later the ‘old’ blog is back – no “risky” recovery needed.

    Download and extract the new WP 2.0 version. If one has access to phpmyadmin then life is easy – backup the existing database (try and minimize taking the ‘cruft’, plugin tables and the like can be recreated as needed by the plugins.. the idea is to give the upgrade process the best chance of success) – open it in a text file and do a ‘search and replace’ for the prefix (e.g. wp_) and replace with something like new_. Create a new db, import the modified sql back in, update the wp-config.php with the new prefix and then perform the wp-admin/upgrade.php process.

    This all has some nifty advantages:

    1) the original files remain intact – reversal takes 10 seconds to rename the new and old directories
    2) the original db (and any additional tables) is still available without a restore (very handy)
    3) the new db can be worked on without impacting the existing blog db (a restore is only as good as the last backup made). πŸ˜‰
    4) one can run concurrent (old + new) blogs to keep a web presence if “diving in the deep end” is a scary thought.

    With this process one is not deleting or modifying any part of the original blog – it’s all intact and 5 seconds of renaming will bring it back. Having the old and new blogs on the go is also useful if one is going to do a more ‘full on’ layout change.

    I’m having extreme trouble, I restored my 1.5.2 db, and now I can’t access my wp-admin panel so I can de-activate all my plugins before attempting the upgrade again, this is the message I get.

    You’ll need to downgrade the wordpress files as well. Might be worth doing a full restore (db and files) then disabling all your plugins before an upgrade (or have a read of my lengthy (heh. sorry) guide above for an alternate solution to upgrades).

    Yep, WordPress 2.0 is not backwards compatible database and file wise, hence the version step.

    Ahhhhh! Installed wordpress 2.0 and everything looked fine. Went to reactive plugins and they ALL fail. I don’t mean they are not compatible. I click the activate link and the browser reports β€œPlugin Activatedβ€?… but it is flat out lying. No matter what I do no plugins are not activated. Even Akismet plugin supplied with WP 2.0 doesn’t activate. HELP?!

    I reactivated my plugins and now for where the author name should be it gives me this:

    WordPress database error: [Unknown column ‘user_level’ in ‘where clause’]
    SELECT COUNT(*) FROM wp_users WHERE user_level > 1

Viewing 15 replies - 1 through 15 (of 102 total)
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