Navigator deck plans, spot the difference?

Hi we're travelling on Navigator in October 2017. On Royal's website there is an updated deck plan dated in effect from 27th April 2017 and the old one but for the life of me I can't see the difference!

Can anyone shed some light?

Most often, some stateroom categories changed.

Most often, some stateroom categories changed.

Well that's not very exciting haha

All RCI ships update their deck plans periodically and, as Bob indicated, the reason typically is to update stateroom categories. The resulting "new" deck plans will be a new mix of subcategories within a given general stateroom category.

After a refurbishment where new staterooms are added, that will appear as well..

The one change I notice when comparing the Navigator deck plans effective April 2017 to earlier Navigator deck plans is that the stateroom category key has been updated so that cabins previously designated as category J, "Interior Stateroom" on decks 9 and 10 are now designated as category VB, "Interior Stateroom with Virtual Balcony".