Document-Based Migration 
Use
The migration of budget documents is mainly for customers intending to migrate during the course of a fiscal year . In this case, data of the first BCS year was previously entered in Former Budgeting, and subsequently needs to be migrated to BCS via documents corresponding to the current year’s data.
Note
One budget entry document in Former Budgeting can lead to several entry documents in BCS, due to specific BCS rules (for example, only one budget category is supported within one entry document).
Multi-year documents that do not follow BCS rules are also split and slightly changed during migration. For example, a transfer between two different years will appear as a return for the sender year and a supplement for the receiver year. Depending on the years involved, possibly only one “side” of the document will be migrated.
For example, the sender part could affect the year before BCS activation. In this case, it will - if so specified - be migrated on a totals basis .
For overall funds, you may need to refer to older documents, since they may relate to years prior to BCS use: However, note that you do not need to use the Former Budgeting functions for this. You can specify that all documents are to be migrated, including the documents of previous years.
More details can be found in the program documentation itself (Transaction FMKUMIGDOC).
Prerequisites
In order to carry out this type of migration, BCS must be activated . Further prerequisites are listed in the program documentation (see below) and should be fulfilled before you migrate your documents.
Procedure
Call up the Implementation Guide, menu path
Public Sector Management
Funds Management Government
Budget Control System
Budgeting
Migration of Former Budgeting to BCS. 
Here, call up the IMG activity “Migrate Budget Documents” (transaction FMKUMIGDOC), and read the corresponding IMG documentation and linked program documentation. When you call the transaction to migrate your budget documents, select between delta and full migration as follows:
Delta migration : only the documents you select which have not yet been migrated are processed during migration.
Full migration : all selected documents are processed. Those which have already been migrated will first trigger a deletion of the corresponding documents in BCS.
After filling in your selection parameters, run the migration program by clicking on the Execute icon.
Result
In the output list, you can see the Former Budgeting documents that have been migrated to BCS.