The DAQCard 6024E is supported in current versions of DAQmx; it's not 'too new.' (The linked document lists 9.0.2 as the current version; it just hasn't been updated since 9.0.2 came out; the latest is DAQmx 9.2.0.). What problems were you having with your device?
Older versions of DAQmx are available for download from this location. Additionally, we still provide Traditional NI-DAQ (Legacy) as well (if you're trying to use an application that was written with the Traditional DAQ API), though we recommend that customers use DAQmx where possible.