Visual Studio upgrade from v1.74 to v1.75 means connection to website fails with 404 error

My watch app allows data to be read from a json file on my website. I use this to simplify setting up details in the app so I can easily simulate different watches.
I been using this successfully on Visual Studio (VS) v1.74 and for a long time before using Eclipse, but today I upgraded to VS v1.75 and it is returning a 404 error in the code.  My web-site logs are not showing any connection from the app simulator.  Has anybody else had a similar issue or has something changed recently?