My seeds were viable even if they were over a year old but I kept mine in the fridge. The germination rate of my fresh seeds and the old ones were about the same but maybe because I used the same media as my other adenium plants. Tried perlite only, they grew but mostly rotted. I let too much moisture in my mini-green house (re: clear plastic cup). On hindsight, maybe I should have removed the plastic cup cover when the seeds sprouted. So lesson learned.
