These steps were sufficient to upgrade Cult Cosmetics to Spree 2.0.4 from 1.3.3. Here are some details on our environment.
- We only have single-variant products
- We are not making use of stock locations (single warehouse)
- Frontend entirely overridden w/ custom bootstrap layout
- Braintree gateway
- Rails 3.2.14
- Upgraded from Ruby 1.9.3-p448 to 2.0.0-p247 in the process (no issues)