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The warnings should not appear in the logs if you follow our recommendation to update first to the latest minor release version before upgrading to the most recent major release, see How to update.

Reloading a page in the editor causes a 404 error

When you open a page for editing and reload it in the browser, an extra semicolon is added to the URL fragment and the server returns a 404 error. Every subsequent reload adds another semicolon. This issue occurs with older versions of the Tomcat application server. To resolve this issue, upgrade to Tomcat 7.0.47+. See 

Tomcat 8 using BCEL may throw class format exception

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