Быстрый интернет-магазин: как сделать?

• Never upgrade on Day 1 release. Give it at least 2 weeks for people to find bugs and any nuances
  
• Don't upgrade if your store is currently successful. There is no point in upgrading just to upgrade.
  Remember you are running a store to make money, not to be a bleeding
  edge cart tester. If you crash your store because you chose to upgrade
  too soon without planning, then you are losing money.
  
• Most 3rd party mods will need to be updated and that takes weeks to months. Depending on the severity
  of the changes, Many mods may need to be rewritten from scratch so there
  may be new fees associated with updated versions.
  
• Upgrades to OpenCart, or most other platforms, are not to be taken lightly. It's not like getting the
  latest updates for Windows.
  
• Any modifications, themes, or addons you had on your old cart will be gone or at least disabled and
  you are basically building it again from scratch. Your customer,
  product, and order data can all be preserved, but most themes and 3rd
  party addons will either need to be reinstalled (when and if there is a
  compatible version made), and many mods that do not have updates will be
  lost.