One of our customers still has Joomla 1.5 and runs a VirtueMart (1.1.9) webshop. The company asked us to update the shop, but to what version is it possible to update VirtueMart?
(and yes, after that we will make a plan to upgrade the site to Joomla 3.1. But this is a new customer so I need a quick fix ;D)
There is no secure version to use with Joomla 1.5 - VirtueMart 2.0.20b "should" work but will need testing and has known security issues. The recommended versions for a secure store is currently Joomla 2.5.14 with VirtueMart 2.0.22d (2.0.22e will be available soon).
A J3 version is not available yet. http://forum.virtuemart.net/index.php?topic=115326.0
In addition you will need to check that the Joomla 1.5 version used by the client is 1.5.26 with the "unofficial" security patch.