Convert the old revenues first

What causes this issue?

You want to plan revenues, but cannot do so at the moment.
This is because the update of the revenue planning has changed for
release 2.1B. Data posted before this release should be corrected
automatically using the XPRA program RKRKP5CH when installing release
2.1B. This program has not yet been started or has not run
successfully. If you planned additional revenues, this would result in
incorrect transaction data.

System Response

Inform your system administrator.

How to fix this error?

Read the release note "CO_PLANUNG_8". You can then run the above
program or run it again.

Error message extract from SAP system. Copyright SAP SE.