Crystal Reports XI - slow response for parameter fields

[#1]

I just upgraded a client that uses Crystal Reports XI (11.0.0.895) to XI R2 SP4 (11.5.10.1263) for compatibility with Windows 10. Ever since, the response time for refreshing reports with parameter fields changed from 20 seconds to 4 minutes. Do they need to upgrade to a newer version of SAP Crystal Reports in order to resolve this issue? Is there a technical resource at SAP that can help me figure this out?

Thank you!

[denis_konovalov]

Both product versions you mentioned are out of support, so getting SAP Resource to help you will be impossible.
If you upgrade to current CR version - you'll have option of SAP support investigation.

What we can do - is try to investigate a bit further via this tread, but there are no guarantees...
So, to start :
1. Are those CR designer (client) or CR Server products ?
2. What is the exact workflow that is slower ?
3. How was upgrade done exactly ?