VM 2.0.x to VM 2.1.x

[MaxP4]

It will be possible to migrate (easily) from VM2.0.x for J2.5 to VM 2.1.x for Joomla! 3.x?

[jenkinhill]

Yes, and you can help with 2.1 testing and development here http://forum.virtuemart.net/index.php?topic=119177.0

[MaxP4]

Sorry, i'm not a developer but I would like to try VM 2.1 on J3.1. Is available any installer?

[jenkinhill]

No you need to build your own installer, see https://dev.virtuemart.net/svn/virtuemart/trunk/virtuemart/vm_build/HOWTO.txt  and  http://dev.virtuemart.net/projects/virtuemart/wiki/Setting_up_a_Development_Environment

But if you don't have developer experience then better to wait for the actual beta releases for the 2.1 series. The stable version for J3.5 will follow once beta/release version testing is complete.