For OCP version 4.17 we need to have below information as release notes.

1) you need to use Loki + ClusterLoggingOperator 6.0
2) you cannot use Loki v6 and ClusterLoggingOperator v5.8
3) Using Elasticsearch + ClusterLoggingOperator v5 is not allowed 
4) ClusterLoggingOperator v5.9 will not be made available in 4.17 this is a planned decision