Follow these instructions to migrate Knowledge__kav articles.

1) Be sure you have migrated all the Data Category Group metadata type first.

2) Next, migrate the 'online' articles. The parent object is Knowledge__kav, and the child object is Knowledge__DataCategorySelection. Move the source Knowledge__kav objects where PublishStatus='online' and the matching field is UrlName. Then run the included Apex script to Publish Draft Articles on the destination org. This will move the destination articles from 'draft' to 'online' status. 

3) Next, migrate the 'draft' articles, if any. This will create the 'draft' articles on the destination. Do not change them to online.

4) If you screw up, we have included the Apex script to Delete Draft Articles. Here are the commands to execute the included Apex classes in the developer console. Each line is a different command to change the state of all the articles.

Id batchJobId = Database.executeBatch(new PublishDraftArticlesBatch(), 50);
Id batchJobId = Database.executeBatch(new ArchivePublishArticlesBatch(), 50);
Id batchJobId = Database.executeBatch(new DraftArchiveArticlesBatch(), 50);
Id batchJobId = Database.executeBatch(new DeleteDraftArticlesBatch(), 50);

5) Here are the available classes and their function.

// Move Draft Articles To Publish (Removes Draft And Archive)

PublishDraftArticlesBatch.cls
PublishDraftArticlesBatch.cls-meta.xml
PublishDraftArticlesBatchTest.cls
PublishDraftArticlesBatchTest.cls-meta.xml

// Move Publish Articles To Archive (Changes Records To Archive)

ArchivePublishArticlesBatch.cls
ArchivePublishArticlesBatch.cls-meta.xml
ArchivePublishArticlesBatchTest.cls
ArchivePublishArticlesBatchTest.cls-meta.xml

// Move Archive Articles To Draft (Creates New Draft Records)

DraftArchiveArticlesBatch.cls
DraftArchiveArticlesBatch.cls-meta.xml
DraftArchiveArticlesBatchTest.cls
DraftArchiveArticlesBatchTest.cls-meta.xml

// Delete All Draft Articles

DeleteDraftArticlesBatch.cls
DeleteDraftArticlesBatch.cls-meta.xml
DeleteDraftArticlesBatchTest.cls
DeleteDraftArticlesBatchTest.cls-meta.xml
