Migration of Former Budgeting to BCS 
The Public Sector Funds Management component contains to sets of functionality for budget management and availability control, Former Budgeting (FB) and the Budget Control System (BCS). The following graphic illustrates the differences in functionality between the two budgeting systems.

Customers currently using Former Budgeting may raise the question of whether to migrate and how the cutover should best be organized. If they do decide to migrate, customers using Former Budgeting can migrate their budget data to BCS in various ways.
Note
Due to the multiple budgeting scenarios used in the public sector, SAP cannot provide a generic migration strategy that can be used by all customers who wish to migrate to BCS. You must set up a customer-specific migration project. For this, SAP has set up guidelines containing possible migration scenarios and providing basic tools for specific straightforward migration scenarios.
Most of the Former Budgeting functionality has been reproduced in BCS, which however also contains completely new screens (for example, a "budgeting workbench") and update tables. One possible approach for the replacement of FB is to create BCS from scratch and not to take over any data from FB (unless re-entered manually). After looking at the design of BCS, this may be an option for some customers.
However, for those customers that would like to continue accessing their existing budget data, SAP now provides a migration toolset. Migration in this context means that budget data gets extracted from the FB database and then updates the corresponding BCS tables. Data migration focuses on the processing of budget data. Note that other data stored in the system, such as master data or availability control records, is not processed during migration. Master data (FM account assignments) remains the same after migration, but AVC must be regenerated in the new BCS context.
Note
If you want to carry out budgeting for funded programs or use the budgeting functions in Grants Management , you have to use BCS, since FB does not support this functionality.
You may wish to not only migrate from FB to BCS, but simultaneously to change or enhance your master data (FM account assignment elements) and budgeting models. Only some of the aspects involved in such changes are dealt with in the current migration scenarios.
Caution
If you want to change your master data structures, that is, the relationships between FM account assignment elements, you may only be able to reconcile the data after migration with difficulty, due to the differing data structures. Please note that such changes of master data structures should not be done within the context of data migration.
See FM Account Assignment Elements in Migration and Organizational Issues Relating to Migration for further information.
You can find all activities related to migration within the IMG .