Update installation guidance for older versions

Author: teodoraberindea

rdp-abap-technical-objects/readme.md

@@ -43,6 +43,10 @@ If you already have **RDP Integration Accelerator V5** installed and want to upg
 - **Packaging Data reports Delta Customizing (will overwrite existing customizing ):**
   - Install **RDP ABAP Technical Objects -> TR 901348.BP7**
 ---
+## **Upgrade from Older Versions of the Accelerator**
+If you are running an **older version** of the RDP Integration Accelerator (prior to V5), you must first upgrade to **V5** before proceeding to V6. 
+
+- Customers using an older version should open a **support ticket** under the **SV-COE-VPT-RDP** component. SAP will provide guidance and the necessary transport requests to first upgrade to **V5** before continuing with the V6 upgrade.
 
 ---
 ## Apply Fixes (Mandatory for All Installations)