This figure consists of a database icon labeled "Database" and three boxes labeled as follows:
Application Tier A: 2.0
Old Application Tier B: 1.5.3
Application Tier C: 1.5.3
The boxes are lined up in one row. The database icon appears above the boxes. Double-headed arrows link each box with the database icon, except for "Old Application Tier B: 1.5.3", which does not have any arrows.