The following instructions are specifically for upgrading an installation of Movable Type from version 2.5 to 2.6 on a DreamHost shared server.

Important Note: These notes cover only an upgrade to 2.6.0. For newer versions of 2.6.x, the specific files that were changed will be different.

Uploading Files

1. Overwrote docs dir with new files
2. Skipped extlib, as no files had changed
3. In images, updated lang-en-us/nav-config.gif, which was the only file to change
4. Overwrote lib dir with new files and directories
5. Overwrote schemas dir with new files
6. Overwrote search_templates dir with new files, since I hadn't modified mine
7. Overwrote tmpl dir with new files and directories
8. Overwrote files in root dir. Need to redo my minor change to textarea500 width in styles.css.
9. At a shell prompt in the mt dir, chmod 755 *.cgi

Running Upgrade Scripts

./mt-upgrade26.cgi

The script altered six MySQL tables and created one new table. After the schema upgrade is complete, you should see the line:

Done upgrading your schema! All went well.

Deleting Upgrade Scripts

rm mt-upgrade*.cgi

Test

Brought up main admin page with no problem. Version 2.6 appeared at bottom of page. Tried to rebuild all files. Rebuild ran to completion, but I got a lot of errors at each step. It was the same error each time.

MT::App::CMS=HASH(0x8378b7c) Use of uninitialized value in substitution iterator at lib/MT/Util.pm line 387

Turned out to be a bug. Newer distributions of 2.6 are fixed. You can also fix it by changing line 387 from:
$s =~ s/([$HighASCIIRE])/$HighASCII{$1}/g;
to
$s =~ s/($HighASCIIRE)/$HighASCII{$1}/g;