Upgrading Zen 6.x-1.x to 6.x-2.x

Do you need to upgrade?

Nope. If you have a working sub-theme using Zen 6.x-1.1, you do not need to upgrade to Zen 6.x-2.x.

The primary purpose of Zen is to aid theme development. If you have finished development and have a working sub-theme, don't worry. Zen 6.x-1.x will remain supported for a long time; there's no need to upgrade just so you have “the latest and greatest.”

Why would you want to upgrade?

You have a contributed theme on Drupal.org and you want it to support Zen 6.x-2.x
You can't upgrade to Drupal 7 for a while, but want to get a head start on migrating your site to Drupal 7. Zen 6.x-2.x uses a lot of the same techniques that are found in Drupal 7 and Zen 7.x-3.x, so upgrading your sub-theme to 6.x-2.x now will split the large upgrade from 6.x-1.x to 7.x-3.x into two smaller upgrades (once to 6.x-2.x and once to 7.x-3.x.)

ROUGH DRAFT: Upgrading Zen from 6.x-1.1 to 6.x-2.0

From comment #1 of #839972: Documentation: Sub-theme upgrade 1.x -> 2.x:

Here's how I upgraded to Zen 6.x-2.0:

Put site into maintenance mode
Follow directions in README files in each folder
Download new Zen
Back up old MYTHEME (into a folder called MYTHEME_deprecated)
Replace all instances of STARTERKIT in STARTERKIT.info.txt with MYTHEME (this is in the documentation). Follow all further documented steps (Rename STARTERKIT folder to MYTHEME; Rename STARTERKIT.info.txt as MYTHEME.info; Copy new MYTHEME folder to your themes directory; etc)
Copy styles from MYTHEME.css (deprecated -- this is the default stylesheet from your old subtheme) into their dedicated style {} in the new STARTERKIT folders (css/blocks.css, css/pages.css, css/layout-liquid.css, etc).
Copy reset styles from old file html-elements.css to new file css/html-reset.css
Zen 6.x-2.0 is very well organized and easy to customize, but some divs and regions are named differently now. Copy and paste the following old styles from MYTHEME.css(deprecated) (or wherever you had them declared in your 6.x-1.x subtheme) under their new style names in css/pages.css and css/regions.css.

(Old) sidebar-left = (New) sidebar-first;
sidebar-right = sidebar-second
.inner = .section .

Navigation: Put old navbar { styles into new Navigation { styles. Do the same for #skip-to-nav styles (this becomes #skip-link)
Move your old images/ folder into the css/ folder (creating the folder css/images/) OR change all your image paths in all stylesheets to match the change in CSS folder hierarchy. Otherwise, your image links from the old theme will be broken.
Delete layout-fixed.css and layout-fixed-RTL.css as specified in documentation (I'm using a liquid layout. Delete the -liquid files if you're using a fixed layout). I'm repeating the documentation here, because I tried to leave in the unused layout files and might have had some problems from the redundancy.
Override in MYTHEME.info: defaults.css and system-menus.css (Optional. Refer to documentation in MYTHEME.info file if you want to do this).
Copy template files from Zen/templates to MYTHEME/templates (also possibly optional)
Enable the new sub-theme in MYSITE.com/admin/build/themes
Re-enable blocks in the new regions at MYSITE.com/admin/build/block. The sidebar blocks were reset when sidebar-left and sidebar-right became sidebar-first and sidebar-second.
Flush cache; run database update (is DB update necessary?); rebuild theme registry.

This is just a start. My upgrade worked, but it took a while to track down the image folder problem, and I had some problems uploading and moving files around.

Does anyone have notes to add to this, or can you point out omissions in the upgrade process?

Thanks for a great theme!

Amy