Reverted GWT version, now it won't run

I already solved this question, this Q&A is purely for future Googlers since it was extremely difficult for me to find the solution开发者_JS百科 via Google - but thanks for looking

I changed my project to GWT 2.3.0 but then had to change back to 2.0.3 (in Eclipse) and now when I run it and try to view it in my browser, I get the following error:

[ERROR] Invalid version number "2.1" passed to external.gwtOnLoad(), expected "2.0"; your hosted mode bootstrap file may be out of date; if you are using -noserver try recompiling and redeploying your app

I've tried cleaning and rebuilding and that doesn't work. How do I fix it?

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Inside your war directory you should have a folder named after your module. Stop debugging if it's running, then delete that module folder (not the entire war folder). Run again; the module folder will be recreated and the error will no longer occur.

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I was facing the same issue. Changed $hostedHtmlVersion="2.1"; to $hostedHtmlVersion="2.0"; in hosted.html file and it worked for me