Travis, Explorer online was updated at the same time as ArcGIS Online. It sounds like your browser has the previous version cached. Clear your browser cache which will ensure you are working latest version of explorer online and try to open the map again. Andy Same issue here (9/28/2011) Cleared Cache in Chrome. Didn't work. Tried it on different workstations and different browsers. Using Chrome and IE8. Same error. Older webmaps seem ok. I can open them in Explorer Online. I create a web map, save, then try and open it in Explorer online and get the "Unsupported webmap version number (1.4) Older webmap that works: http://www.arcgis.com/home/item.html?id=cc57979c38b64350a34800972c8de266 tests 1, 2, and 3 that get the error: http://www.arcgis.com/home/item.html?id=877346d0a7d0406dac24df225d9cd9c8 http://www.arcgis.com/home/item.html?id=973e5897ead945a59a2b121d63d331bb http://www.arcgis.com/home/item.html?id=5539a1f0423f4f138e7f2f417a5cc33e
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