I was concerned to see that SQLite was deprecated in movabletype 5.0, but I went ahead and upgraded my blog. I followed the standard procedure, copy the new version over the old version then run the mt-upgrade.cgi via the browser. The upgrade script never made it to migrating the database. When this happened I just used the "Upgrade a large database" instructions
$ export MT_HOME=/var/local/mv
$ cd $MT_HOME
$ perl ./tools/upgrade --name superuser
upgrade -- A command line tool for upgrading the schema for Movable Type.
* Upgrading database from version 4.0070.
* Upgrading table for Website records...
* Upgrading table for MT::Entry::Summary records...
* Upgrading table for entry_rev records...
* Upgrading table for Entry records...
* Upgrading table for Asset Placement records...
* Upgrading table for Session records...
* Upgrading table for MT::Author::Summary records...
* Upgrading table for User records...
* Upgrading table for template_rev records...
* Upgrading table for Template records...
* Upgrading table for Permission records...
* Upgrading table for Comment records...
* Rebuilding permissions...
* Rebuilding permissions... (100%)
* Updating existing role name...
* Populating new role for website...
* Migrating mtview.php to MT5 style...
* Assigning new system privilege for system administrator...
* Assigning to jason...
* Updating existing role name...
* Populating new role for theme...
* Upgrading Asset path informations...
* Classifying blogs...
* Classifying blogs... (100%)
* Merging dashboard settings...
* Merging dashboard settings... (100%)
* Migrating existing 1 blog into websites and its children...
* Generated a website http://mischievous.org/
* Moved blog Pseudointellectual Appendification (http://www.mischievous.org/) under website mischievous.org
* Creating new template: 'Comment Listing'.
* Database has been upgraded to version 5.0016.
Upgrade complete!
