I need an AirPort Utility that works with OS X V. 10.11.2

AirPort Utility 6.3.1 is for Mac OS X V 10.10 My MacBook Pro has OS X version 10.11.2 El Capitan. I need to install an AirPort Utility for my O/S so I can change the channel assignment. My download speed is supposed to be up to 200Mbps and a lot of the time it's under 100Mbps. Sometimes it's 130Mbps, like right now. TWC said I should be using channels 1, 6 or 11, but I can't get into my AirPort Time Capsule, to check or change the channel assignment.

Does Apple have an AirPort Utility that works with El Capitan or am I screwed?