I upgraded a site collection from SP 2010 to SP 2013. It contain a site template called "My Project Site". There is a web part which creates new site using this site template.
Problem is on 2013 the sites being created have 2010 look and feel. All existing sites that were created on 2010 have 2013 look and feel (after I upgraded site collection) so the problem is only with newly created sites.
I opened manifest.xml file of (My Project Site.wsp) and the SharePointProductVersion property is set to 15.0.4833.1000 (which I fixed yesterday as this was another issue)
How do I fix this issue?
EDIT
This is how it looks like. 2010 look and feel and all messed up.