Package dependencies and uploading
Packages can have dependencies on platform features and/or other packages. You can review and manage these dependencies through the usage of the Package Detail page and the use of dynamic coding conventions, as described here.
While some features of Salesforce are common, customers can purchase different editions and features according to their needs. Developer Edition organizations have access to most of these features for free. This means that as you develop your application, it is important to understand when and when not to use those features (this is done in order to avoid unwanted dependencies that might block or inhibit the adoption of your application).
By default, when referencing a certain Standard Object, ...