Drupal 6 to 7; Drupal 5 to 6; + Drupal @ Upcoming Ohio LinuxFest 2009

Here are the notes from the D7 discussion. We talked mostly about the APi and UI changes and did not get into the theming changes, of which there are a ton, I encourage themers to look at this, there's a link at the bottom of the notes.

Requirements
PHP 5.2 +
MYSQL 5.0 +

Modules

Ships with the following enabledfields
vertical tabs
path
search
admin account
core required is gone on modules page
clean urls installed by default on install (option to turn off)
Poormans Cron in core (can be shut off)

Without the following
Page type, story type
blocks modules is optional
there is no profile module anymore as that is provided by fields api
image api and image cache are in core, image field is coming

Block changes
block module can be disabled
content is a block
Per-content type block visibility that we ripped out of core in Drupal 5 or so is now back! There'll now be a nice little selection for showing a block only on "Story" nodes, for example.
A whole gaggle of formerly "special" things are now just regular old blocks. Footer message, feature-specific help text, mission statement, and even $content! This means they can be more precisely positioned and have the same configurable visibility as other blocks in the system.

top level nav is totally changed
no more site maintenance or site building it's now content, structure, appearance, people and Configuration and Modules

CCK -> fields
Form element titles no longer end with a colon by default. Goodbye, "How old are you?:" You will not be missed!
all node fields are fields API fields, meaning you can delete body and you can add fields to user (ie no profile module) add fields to taxonomy
file field in core

create content page
Edit summary/hide summary (ie teaser) in the node pages
Label text format replaces input format
primary links now main menu

Edit content type
Machine readable name now derived from plain english name
display settings (includes per type teaser length and moved post info (suthor and date ) form theme global settingds

Database
New database layer
SQLLite (means possible live cd support for drupal demos)
True PostGres support
InnoDB support for MYSQL
Foriegn key's supported in Schema API

Major changes to code
Simpletest in Core
Hook registry (register what module is calling what hook)
disable/enabling modules now causes modules to call hook implementations for that module
Tons of work is being put forth into an effort to move "Plugin Manager" into core. What is Plugin Manager you ask? Can you say automatic project updates from within Drupal? I knew you could! So far we have some underlying libraries for handling SSH/SFTP/FTP communication, but there's still much more work to be done before this is ready.

Helpful links
Changelog http://drupal.org/node/156281

API changes http://drupal.org/update/modules/6/7

Theme engine pages http://drupal.org/update/theme/6/7#granular

It may work on MYSQL 4, but it won't be supported

http://drupal.org/requirements