A quick step-by-step on how to migrate from the ordered index to lucene.
Assuming you have the following ordered index configuration
{ ... "declaringNodeTypes" : "nt:unstructured", "direction" : "ascending", "propertyNames" : "foobar", "type" : "ordered" ... }
the related lucene configuration will be
{ "jcr:primaryType" : "oak:QueryIndexDefinition", "compatVersion" : 2, "type" : "lucene", "async" : "async", "indexRules" : { "jcr:primaryType" : "nt:unstructured", "nt:unstructured" : { "properties" : { "jcr:primaryType" : "nt:unstructured", "foobar" : { "propertyIndex" : true, "name" : "foobar", "ordered" : true } } } } }
for all the details around the configuration of Lucene index and additional flags, please refer to the index documetation.