At the time of writing there are three user interface themes. There are two classic themes, namely Classic 2005 and Classic 2010, and there is a new theme called Lightning Experience.
Browser support and functionality varies depending on whether Salesforce Classic or Lightning Experience is used, and are described in more detail later on in this section.
All screenshots and setup details this book shows the Classic 2010 user interface theme.
The difference in the classic themes can be seen in the following screenshot, which appears when you attempt to change from the Classic 2005 to Classic 2010:
Not only does the new user interface theme change the look and feel of Salesforce, but it may also ...