Question about upgrading to Couchbase server version 7.6.1

We are planning to upgrade our Couchbase server Enterprise version from 6.5.0 4960 to the latest version, 7.6.1. Should the upgrade path be from 6.5.0 to 7.2.3 to 7.6.1? Or should it go from 6.5.0 to 6.6 to 7.2.3 to 7.6.1? When performing a live rolling upgrade, should the SDK be upgraded before the server upgrade, set to the default bucket, and then, after upgrading to version 7.x, should it be placed into scope and collection?

Additionally, if I upgrade from version 6.x to 7.x, data is transferred to location A Bucket._default._default in 7.x version A Bucket from 6.x version A Bucket.
Is it impossible to move data from A Bucket._default._default to A Bucket.B_scope.C_collection through XDCR? The question is whether XDCR does not work within the same bucket?

cc @neilhuang

This is correct. XDCR will not be able to replicate from a bucket to itself.

I saw the blog post you uploaded.
When I checked the upgrade document, it said to go to 6.6 if I want to upgrade to 7.6.1,
but is there no problem upgrading directly from 6.5 to 7.2.3?