Or we can have one Drupal Legacy Module that we can suport the modules of previous drupal release.
No we can't. The API changes in Drupal 7 include things like changing the way modules are defined in .info files to make them compatible with the registry, and changing the syntax of every single database query. It's impossible to make a module which would allow you to run a Drupal 6 module on Drupal 7 with no changes, and that's a very, very good thing. It's already been said once in this thread, but the reason it took so long for contrib to catch up to Drupal 6 was a massive refactoring of CCK, Views, wysiwyg API and other modules all the same time - and the fact that contrib has a very complex web of dependencies (baz module extends foo module which extends bar module, so can't do an update until both bar and foo are upgraded). A Views 2 which was backwards compatible with Views 1 wouldn't be half as much fun - and if you just want to use the same D5 modules you were using already without any of the advantages, why upgrade at all? We don't make API changes for fun, we make them because we have to - either to correct previous mistakes or open up new possibilities. If an API doesn't need to change then it usually doesn't - for example hook_menu() is pretty much exactly the same between 6 and 7. All the effort talking about backwards compatibility should instead be focused on http://drupal.org/project/deadwood and http://drupal.org/project/coder - and also on the Field API and Views related patches to core which will be necessary for field, views, and views-dependent modules to upgrade to D7. Coder already has an initial port to Drupal 7 and does a great deal of the work required to update a module. The better it gets, the less work module maintainers (or upgrade patch contributors) need to do to get a basic port of their module going. Combined with unstable releases, it's quite possible to start upgrading modules to Drupal 7 now - in fact there's 7 pages of modules which have some kind of port in the works, months before code freeze - something we've never, ever had before. http://drupal.org/project/modules?filters=drupal_core:103&solrsort=sort_titl... Nat