Seasonal adjustment is an important step of the official statistics business architecture and harmonisation of practices has proved to be key element of quality of the output. In this spirit, since the 90s, Eurostat has been playing a role in the promotion, development and maintenance of a free software solution (Demetra) for seasonal adjustment in line with established best practices.
In 2011 a new software, called Demetra+, was released. It consists in a .NET encapsulation of the two leading algorithms in the domain - Tramo-Seats and X12-Arima, which provides a common approach for seasonal adjustment. The current version of Demetra+ (1.0.4) can be downloaded form the Cros-Portal (http://www.cros-portal.eu/content/seasonal-adjustment)
The SAT project aims at replacing the .NET application. It will provide, through Java modules, an object-oriented toolkit for time series analysis in general and for seasonal adjustment in particular. The new implementation will make easier specific in-house applications as well as extensions of the main application, called JDemetra+. The current project is designed for developers.