If I update the items in MM with http://192.168.xx.xx:8080/openhab/?item=RTR_EG_WoZi_actualTemp&state=24 I get back:
{"status":"success","payload":{"item":"RTR_EG_WoZi_actualTemp","state":"24","timestamp":"2017-02-15T10:23:17.519Z"}}
But as you can see in the screenshot, it’s still not updated there. Did I miss something?

my config.js:

		{
			module: 'mmm-openhabfloorplan',
			position: 'bottom_left', // this can be any of the regions
			config: {
				updateInterval: 60 * 60 * 1000, // refreshing all windows / lights / labels once per hour; 0 to disable periodic update
				draft: true, // if true, all lights, windows, and label names are shown; if false, get states from openhab
				openhab: {
					url: "http://192.168.xx.xx:8080", // must not have a trailing slash!
					// user: "", // only if you have authentication enabled
					// password: "", // only if you have authentication enabled
				},
				floorplan: {
					image: "floorplan-default.png", // image in subfolder 'images'; change to floorplan.png to avoid git repository changes
					width: 400, // this must be the width of the image above
					height: 333, // this must be the height of the image above
				},
				// light: { // this part shows default settings for lights; may optionally be overwritten
				//  image: "light.png", // located in subfolder 'images'
				//  width: 19, // image width
				//  height: 19, // image height
				// },
				// window: { // this part shows default settings for windows; may optionally be overwritten
				//  defaultColor: "red", // css format, i.e. color names or color codes
				// },
				// label: { // this part shows default settings for labels; may optionally be overwritten
				//  defaultColor: "grey", // css format
				//  defaultSize: "medium", // value of font-size style, e.g. xx-small, small, medium, large, x-large, 1.2em, 20px
				// },
				lights: { // list all light items to be shown (must be of openhab type Switch or Dimmer)
					// format: "openhab item (name is case-sensitive!): { left, top }"
					Light_EG_WoZi_LG1:      { left: 80,  top: 110 },
					Light_EG_WoZi_LG2:    { left: 80,  top: 240 },
					Light_EG_WoZi_LG3:      { left: 310, top: 5 },
					Light_EG_WoZi_LG4:     { left: 70,  top: 5 },
					Light_EG_Flur_Ceiling:  { left: 238, top: 310 },
					Light_EG_Windfang_Ceiling:  { left: 40,  top: 310 },
					Light_EG_WC_Ceiling: { left: 340, top: 310 },
					Light_EG_Kueche_Ceiling:     { left: 280, top: 110 },
					Light_EG_WoZi_WandEss:       { left: 210, top: 220 },
				},
				windows: { // list all window / door contacts to be shown (must be of openhab type Switch or Contact)
					// openhab item: left, top, radius (draws quadrant), midPoint, and optionally counterwindow and color
					Reed_Door:           { left: 232, top: 289, radius: 32, midPoint: "bottom-right", color: "orange" },
					Reed_Entry:          { left: 188, top: 298, radius: 23, midPoint: "bottom-left" },
					Reed_Living:         { left: 12,  top: 106, radius: 29, midPoint: "top-left", counterwindow: "vertical" },
					Reed_Dining_right:   { left: 170, top: 12,  radius: 29, midPoint: "top-left", counterwindow: "horizontal" },
					Reed_Dining_left:    { left: 141, top: 12,  radius: 29, midPoint: "top-left" },
					Reed_Kitchen:        { left: 283, top: 44,  radius: 30, midPoint: "top-right", color: "orange" },
					Reed_Utility:        { left: 359, top: 180, radius: 29, midPoint: "bottom-right" },
					Reed_Sleeping_right: { left: 12,  top: 231, radius: 30, midPoint: "top-left" },
					// openhab item: left, top, width, height (draws rectangle), and optionally color
					Reed_Sleeping_left:  { left: 90,  top: 301, width: 37, height: 20 },
					Reed_Bath:           { left: 275, top: 301, width: 37, height: 20 },
				},
				labels: { // list all strings to be shown (may probably be any openhab type, resonable for String and Number)
					// openhab item: left, top, and optionally color, font size, prefix, postfix, and number of decimals for floating numbers
					RTR_EG_WoZi_actualTemp:         { left: 22,  top: 72,  decimals: 1 },
					RTR_OG_Schlafen_actualTemp:   { left: 200, top: 25,  color: "white", size: "x-small" },
					RTR_OG_Bad_actualTemp:    { left: 135, top: 25,  color: "white", size: "x-small" },
					RTR_OG_KiZiOst_actualTemp:        { left: 345, top: 220, color: "green", decimals: 2 },
					RTR_OG_KiZiWest_actualTemp: { left: 22,  top: 242, prefix: "outside: ", postfix: "°C" },
				}
			}
		},