Hi Shivam
1. Latest version Netweaver 7.4
2. Dual stack supported version NW7.3 (Without Split)
3. From the Current version NW 7.0 SP18 to either with dual stack you can upgrade NW 7.3 or Dual stack split with NW 7.4 along with kernel 7.21 or 7.22.
Regards
SS