Updated the instructions a bit. Please do not post bug reports here. Please post them to the bug tracker.

Here are some steps to take when upgrading from K2 0.9.1:

  1. Optional: Upgrade to WordPress 2.1. The next version of K2 will require it.
  2. Important: Deactivate the WordPress Widgets plugin.
  3. Optional: In the K2 Options panel, click on the Uninstall K2 button. Warning: This will deactivate and clear your K2 options. Ignore the headers error that you get.
  4. Rename the old k2 folder to something else.
  5. Download K2 0.9.5, decompress and upload the k2 folder to your WordPress themes folder.
  6. Copy any third-party schemes from the old styles folder to k2/styles.
  7. Copy any custom header images from the old images/headers folder to k2/images/headers.
  8. You can now delete your old K2 folder.
  9. Set the proper permissions to the headers folder: world writeable (777).
  1. Activate the new K2 from the Themes panel.