Posting in Previous Releases
You can carry out posting to Accounting, even if your Human Resources and Accounting components are in an R3 System with an earlier release than 4.0A, or in an R/2 System. Normally, functions are only supported if they are available in both Payroll and Accounting releases.
If your Accounting
component is in an R/3 System with an earlier release than 4.0A or in an R/2
System, you must specify, in Customizing for Posting for
Accounting , the company codes that exist within the system. You
must also carry out the step 
Set
Up Export to R/2 System or R/3 System < 4.0.
For more information on Customizing posting in previous releases, refer to the Implementation Guide (IMG) for ALE Business Processes. The following is also relevant if posting takes place using file transfer instead of using the ALE interface:
- If your Accounting
component is in an R/3 System with an earlier release than 4.0A or in an R/2
System, refer to the information in the scenario HR
Rel. 4.0A and Acctg Release earlier than 4.0 .
- If your Human
Resources component is in an R/3 System with an earlier release
than 4.0A or in an R/2 System, refer to the information in the scenario
HR Rel.earlier than 4.0A and Acctg Rel. from 4.0A
Further Notes
For more information, refer to the SAP Library under Payroll -> country -> Subsequent Activities -> Posting to Accounting -> Steps in Posting to Accounting -> Posting in Previous Releases.