Currently, the StandardSiteUrlFactory class doesn't append the query parameter into the newly created url!

Another suggestion, Add new attribute (e.g. mParameter,mParamValue) to the SiteSwitcherHandlerInterceptor.java which supports cases then mobile site is based on the query parameter.

For example for testdomain.com it redirects to testdomain.com?${mParameter}=${mParamValue}

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Reza