mapbox/tilemill — Issue #1250: Can't zoom past 18
Author: willwhite
Created: 2012-01-27 22:04:53+00:00
State: open

From: http://support.mapbox.com/discussions/tilemill/462-080-project-updated-to-090-max-zoom-now-18

In the project settings view and the main map preview, the max zoom is 18--even if you drag the project settings slider out to 22.