My company recently switched from SharePoint Server 2010 to SharePoint Server 2013, but for now it is the 2010 Emulation Mode. One of the older (created on SharePoint Server 2007) Visual Studio SharePoint projects does not work after the migration and I need to rewrite it. Eventually we will shut off 2010 Emulation for a pure 2013 environment so my question is - will a SharePoint 2013 Project work on a SharePoint 2013 Server emulating SharePoint 2010 and once we shut off the 2010 Emulation, will it still work?
So that emulation is called 'v14.5' mode. You will build your new project (or upgrade it) to use v14,v15 mode in your Visual Studio package properties. This will deploy it to the 14 and 15 hive, making it compatible with both v14.5 and v15 site collections on SharePoint 2013.