Hi,
CleanMart got a new version couple hours ago (v3.9.4). The new version is fully supported by VM3.0.14, also it includes varies improvements. See here for more info:
www.flexiblewebdesign.com/forum-virtuemart-2-template-support/1379-cleanmart-updates-check-and-request
CAUTION: Using any older CleanMart with Virtuemart3.0.14 is
not OKAY!. Old versions cause a critical problem with VM3.0.14. Completing the checkout becomes impossible. If you update Virtuemart to VM3.0.14 make sure to update the CleanMart to v.3.9.4 as well.
(for future reference, no need to worry about the Joomla version, you can safely update Joomla whenever the new one comes up -- but check with the
www.virtuemart.net to see if Virtuemart Core Component supports that new Joomla version as well. CleanMart is rely on Virtuemart Core Component. So, as long as Virtuemart Core Component works on the new Joomla version that comes up, CleanMart will work too.. I suppose, updating Joomla is safe until Joomla4.0 is released.)
Regards.