SUM error during S/4HANA Conversion

Hi experts,

I'm trying to convert our development system to S/4HANA On-premise 1511 SPS01. I could successfully generate the stack.xml file by using Maintenance planner. However, SUM shows the following error message during the conversion process.

Stack file is invalid: component 'ECC-SE' (stack release 605 < source release 800)

I tried following things, but still does not work...

- Regenerate the stack.xml file -> "ESA ECC-SE 800" were not shown up in the list.

- Download the support package in software download center directly ->  "ESA ECC-SE 800" is not available at this time.

Could anyone give me a solution?

Best regards,

Taichi