For AIX (all 64 bit) we currently have
Replication Server/15.7.1/EBF 21656 SP110 rs1571sp110/RS6000/AIX 5.3/1/OPT64/Wed Sep 11 12:46:38 2013
This works with both ASE 15.5 and ASE 16.0 SP02
It is of course better to go with the latest and greatest one if you can, so that
- you are not pressed for the next upgrade or
- face the risk of being out of support right after.
HTH
Avinash