silverstripe/cms: ^4.0
silverstripe/lumberjack: ^2.0
silverstripe/tagfield: ^2.0
silverstripe/widgets: *
silverstripe/comments: *
composer require silverstripe/blog
Aside from the framework and CMS upgrades required the blog module should not require anything extra to be completed.
If you're upgrading from blog version 1.0 to 2.x you will need to run the BlogMigrationTask. Run the task using dev/tasks/BlogMigrationTask either via the browser or sake CLI to migrate your legacy blog to the new version data structure.