Hi,

no the Joomla update is not related at all with this kind of problem.
Probably there is a misconfiguration or a page cache enabled, to ensure that this is not the case please have a look here: http://storejextensions.org/faq/can-i-use-cache-when-responsivizer-is-installed.html

Also if you have installed the No Number Advanced Template Manager plugin it won't work.
If the Advanced Template Manager System plugin is enabled it overrides the standard Joomla templating system thus making not possible to perform the mobile template switching. Moving the No Number Advanced Template manager plugin to load before the Responsivizer Template Switcher could also works.

If you can't find the issue contact me at This e-mail address is being protected from spam bots, you need JavaScript enabled to view it providing an admin account so that i can analyze it.

Cheers,
John